CN107761541A - A kind of construction method suitable for large span arch bridge basis - Google Patents

Abstract

The invention belongs to the technical field of bridge engineering, and in particular relates to a construction method suitable for the foundation of a long-span arch bridge, comprising the following steps: A, excavating a trench: excavating a trench on the ground corresponding to the support of the arch bridge foundation, the The lower part of the trench is located in the bearing layer; B, pouring support: pour concrete in the trench excavated in step A, and obtain the support after hardening; C, excavating the foundation pit: for the soil layer above the bearing layer Excavation until the bearing layer; D, pouring foundation slab: pour concrete in the foundation pit formed in step C to obtain foundation slab; E, pouring abutment: after the foundation slab in step D is hardened, pour abutment on the foundation slab . The construction method of the present application can reduce the excavation depth on the one hand, so that the foundation structure of the present application can be applied to the thicker geological conditions of the overburden; The structure can be applied to the foundation of long-span arch bridges.

Description

A construction method suitable for the foundation of long-span arch bridges

technical field

The invention belongs to the technical field of bridge engineering, and in particular relates to a construction method suitable for the foundation of a long-span arch bridge.

Background technique

The bridge foundation is an important part of the bridge structure, which plays an important role in transmitting the self-weight and load of the bridge structure to the foundation.

For arch bridges, the superstructure of the arch bridge can convert a large part of its own weight and load into internal compressive stress. Due to this characteristic, compared with bridges with other structural forms, the load transmitted to the foundation by the arch bridge is in addition to the vertical load. , there is also a large lateral load.

Based on the above-mentioned structural characteristics, in the current arch bridge design, its foundation form is usually designed as an open-cut enlarged foundation or a pile group foundation. These two basic forms of both have obvious defects, as follows:

Open-cut enlarged foundation: Carry out open-cut construction at the foundation position, and after excavating to the bearing layer, pour the foundation on the bearing layer. This form of foundation has greater rigidity and horizontal and vertical bearing capacity. It is the most commonly used foundation form in the design of arch bridges.

However, the open-cut enlarged foundation has extremely high requirements on the properties of the bearing layer of the foundation, and a rock layer with a high bearing capacity is required as its bearing layer. Therefore, for the geological conditions with thick covering layers, the construction cost will increase sharply, and this foundation form is obviously not applicable under the limited cost budget.

Pile group foundation: setting multiple foundation piles at the foundation position can relatively reduce the construction cost compared with the enlarged foundation of open cut, and then it can be used in the construction situation with thick foundation covering layer.

However, the lateral bearing capacity of the pile group foundation is small. For small-span arch bridges, the lateral load transmitted to the foundation is small, so the pile group foundation can be considered. However, for long-span arch bridges, because the lateral load transmitted to the foundation is extremely large, for example, it can reach more than 200,000KN, so if the pile group foundation is still used, the construction cost will also increase sharply. In the case of limited budget, the group Pile foundations are obviously no longer suitable.

Therefore, it is necessary to design a new type of arch bridge foundation structure that is suitable for long-span arch bridges and can save construction costs.

Contents of the invention

The object of the present invention is to provide a novel arch bridge foundation structure suitable for long-span arch bridges and capable of saving construction costs, in view of the shortcomings of the current arch bridge foundation structure: being greatly restricted by geological conditions and high construction costs.

In order to realize the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A long-span arch bridge foundation, comprising an abutment and a force-bearing layer for supporting the abutment, and also includes a support, the support is arranged on the periphery of the force-bearing layer, and the support is used for supporting the bearing layer.

The foundation structure of the present application is provided with supports for supporting the force-bearing layer in the lateral direction, thereby greatly improving the lateral load-bearing capacity of the foundation of the application. The size of the supports is based on the actual construction. Determine the magnitude of the lateral load. Due to the setting of the support, the lateral bearing capacity of the foundation structure is improved, thereby reducing the requirements for the bearing capacity of the bearing layer. Therefore, in actual construction, the excavation depth of the foundation can be reduced, the construction cost can be reduced, and the construction period can be shortened. Moreover, it can be applied to more geological conditions; on the other hand, it is also due to the strengthening of the lateral bearing capacity of the bearing layer of the foundation, so that the use of the basic structure of the application can improve the greater supporting capacity, and then can be applied to large-span , and even the construction of super-long-span arch bridges.

Preferably, the support member is arranged vertically. The support is arranged vertically, which can effectively avoid the vertical load on the support. In this way, on the one hand, the support can only bear the lateral load of the horizontal method, so as to avoid excessive vertical load and damage the support, and ensure the structural safety of the support. On the other hand, it makes the force of the support more clear, facilitates the structural design, reduces the uncertain factors in the design process, and thus improves the reliability and safety of the structural design.

Preferably, the support member is a hollow cylindrical structure with both ends open, and the inner wall of the support member cooperates with the side wall of the force-bearing layer. Setting the support as a hollow cylindrical structure, on the one hand, coordinates the various parts of the support in the circumferential direction, and acts as a hoop for the internal bearing layer, which can significantly improve the bearing capacity of the geological layer Capacity, deformation modulus and seismic performance, and then improve the lateral load bearing capacity of the support; on the other hand, when the bearing capacity of the bearing layer is poor, the bearing layer can be grouted, and the support The components can also effectively avoid grouting, save construction costs and shorten the construction period, and at the same time improve the quality of grouting and ensure the structural reliability of the bearing layer.

Preferably, the support member has a horizontal cross-sectional shape of a circle, an oval ring or a square ring.

Preferably, the support is a continuous wall. The continuous wall structure is adopted. In actual construction, trenches are first excavated on the ground corresponding to the continuous wall and reinforced concrete is poured. When the continuous wall reaches the design strength, the soil in the wall is excavated. , Due to the support and closure of the diaphragm wall, there is no need to set up internal support and water sealing structures during the excavation process, so the excavation process is also simplified and construction costs are saved.

Preferably, a foundation plate is further arranged on the force-bearing layer, and the matching area between the foundation plate and the force-bearing layer is larger than the bottom area of the abutment, and the abutment is arranged on the foundation plate. By setting the foundation plate, on the one hand, it expands the force-bearing area of the force-bearing layer and reduces the vertical stress. On the other hand, it also makes the force of the force-bearing layer more uniform, thereby further reducing the bearing capacity of the force-bearing layer requirements.

Preferably, the foundation plate is a concrete structure poured on the bearing layer. The base plate is formed by pouring. During the pouring process, part of the mixture flows into the gap between the bearing layers. On the one hand, it plays a certain role in strengthening the bearing layer. On the other hand, it also improves the foundation plate. The reliability of the connection with the bearing layer ensures the reliable transmission of lateral loads and vertical loads.

Preferably, the upper edge of the supporting member continues to extend upward after exceeding the upper edge of the bearing layer, and covers the side wall of the foundation plate. In this way, while the support strengthens the lateral load-bearing capacity of the load-bearing layer, it also strengthens the lateral load-bearing capacity of the foundation plate, and, because the base plate part shares the lateral load, the bearing force is further reduced The lateral load on the bearing layer further reduces the requirement on the lateral bearing capacity of the bearing layer.

Preferably, several shear keys are also connected between the base plate and the abutment. Through the setting of the shear key, the transmission of the lateral load between the abutment and the foundation plate is further ensured, thereby ensuring the reliable transmission of the lateral load by the foundation structure of the present application.

Preferably, backfill soil is also filled in the excavated space on the foundation plate.

Preferably, a counterweight is further arranged on the base plate, and the counterweight is used to adjust the stress distribution of the force-bearing layer. According to the stress distribution in the actual design structure, set the counterweight to adjust the stress. In this way, the adaptability of the foundation structure of this application to different geological conditions can be further improved, and the force of the bearing layer can be further optimized conveniently. In turn, the requirements for the geological performance of the bearing layer are further reduced.

Preferably, the weight, shape and position of the counterweight ensure that the stresses of the force-bearing layer on the same horizontal plane are consistent everywhere. In this way, the force on each position of the bearing layer and the foundation plate is relatively uniform, avoiding the situation of large local stress, ensuring that the components can fully exert their mechanical properties, and reducing the risk of uneven settlement caused by uneven force on the bearing layer .

Preferably, the side wall of the counterweight is attached to the side wall of the abutment. The side walls of the counterweight and the side walls of the abutment fit together, so that the counterweight can transmit the lateral load on the abutment while acting as a counterweight, further reducing the load on the bearing layer. Lateral load, which further reduces the requirements on the lateral bearing capacity of the bearing layer.

Preferably, several shear keys are also connected between the counterweight and the base plate. The base plate can share the lateral load on the counterweight, and on the other hand, it also ensures the stable position of the counterweight and prevents the counterweight from shifting.

Preferably, the shear key is a steel bar segment.

Preferably, the upper edge of the supporting member continues to extend upwards to the ground after exceeding the upper edge of the foundation plate. In this way, the lower end of the support is located in the bearing layer, and then extends upward to the ground. On the one hand, it is further convenient for excavation construction; More reliable transmission of lateral loads, thereby ensuring the stability of the foundation structure and reducing the requirements for the lateral bearing capacity of the bearing layer.

Preferably, an inner liner is provided on the corresponding inner wall of the support above the base plate, the inner liner is hollow and cylindrical, and the outer wall of the inner liner matches the inner wall of the support. By setting the lining, the support strength of the support is increased, and the structural reliability of the support is improved.

Preferably, the inner lining is a reinforced concrete structure.

Preferably, the lower end of the inner liner is arranged on the base plate, and an anti-adhesion layer is arranged between the lower end of the inner liner and the base plate to prevent the inner liner from being connected to the base plate.

Preferably, the anti-bonding layer is an asphalt layer coated on the lower end of the lining and/or the foundation plate.

As another preference, the lower end of the lining and the base plate are clearance fit.

In the above scheme of the present application, an anti-adhesion layer is set between the lower end of the inner lining and the foundation plate, or a gap fit is set between the lower end of the inner lining and the foundation plate. In this way, the gap between the base plate and the inner lining There is no vertical constraint. When the foundation slab is subjected to the vertical load imposed by the arch bridge, the foundation slab will not pull the lining, thereby avoiding the vertical load from pulling the support. The danger of the support being pulled and damaged further ensures the structural stability and reliability of the support; this setting can also avoid the shrinkage of the foundation slab under the temperature stress caused by the heat of concrete hydration after the foundation slab is poured , being pulled by the inner lining to produce cracks; on the other hand, it also makes the stress of the internal structure of the foundation of the application clearer and simpler, which can greatly reduce the difficulty of design, and also reduce the possible uncertain factors in the design work, thereby improving the The stability and reliability of the design structure.

The application also discloses a construction method applicable to the foundation of a long-span arch bridge, comprising the following steps:

A. Excavating trenches: Excavating trenches on the ground corresponding to the arch bridge foundation supports, the lower part of the trenches is located in the bearing layer;

B, pouring support: pour concrete in the trench excavated in step A, and obtain the support after hardening;

C. Excavation of foundation pit: Excavate the soil layer above the bearing layer until the bearing layer;

D, pouring foundation slab: pouring concrete in the foundation pit that step C forms obtains foundation slab;

E, pouring abutment: after the base plate of step D is hardened, pour the abutment on the base plate.

In the construction method of the present application, by excavating the trench, the lower part of the trench is located in the bearing layer, and the support obtained by pouring is embedded in the bearing layer, so that the bearing capacity of the bearing layer is improved. In this way, for the same supporting strength, The load-bearing capacity requirements for the bearing layer can be reduced. On the one hand, the excavation depth can be reduced, so that the foundation structure of the application can be applied to the geological conditions with thick covering layers; on the other hand, for the same bearing layer , adopting the basic structure of the present application can greatly improve the bearing capacity of the foundation, so that the basic structure of the present application can be applied to the foundation of long-span arch bridges.

Preferably, a step F is also provided after the step E,

Step F, setting the counterweight: pouring the counterweight on the foundation plate, so that the force applied by the foundation plate to the force-bearing layer is uniform. When carrying out the structural design of the foundation, the size and position parameters of the counterweight are determined. Through the counterweight, the force-bearing layer is subjected to relatively uniform pressure from the foundation plate to maintain the stability and reliability of the foundation structure.

Preferably, the abutment in step E and the counterweight in step F are poured at the same time. Simultaneous pouring, on the one hand, can save construction procedures and reduce construction costs; on the other hand, it can also make the connection between the abutment and the counterweight closer, ensuring the stability of the load transmission between the abutment and the counterweight .

Preferably, a step A1 is also provided between steps A and B,

Step A1, setting up reinforcement bars: arrange reinforcement bars or reinforcement cages in the trenches excavated in step A, so that the supports obtained by pouring in step B are reinforced concrete structures. The supporting member is set as a reinforced concrete structure to further improve the structural strength of the supporting member, and further enhance the strengthening effect of the supporting member on the transverse bearing capacity of the foundation.

Preferably, in said step C, step C1 is also included,

Step C1, setting the lining: pouring the lining on the inner wall of the support above the foundation plate.

Through the setting of the inner lining, the structural strength of the supporting member is further strengthened, and the stability and reliability of the basic structure are further improved.

Preferably, in the step C1, the pouring of the inner lining is constructed by a reverse method.

Preferably, in the step D, when pouring the foundation slab, several shear keys are vertically arranged at the positions corresponding to the abutment and the counterweight, and the lower half of the shear keys are located on the base In the plate, the upper part of the shear key protrudes from the base plate, and when steps E and F are performed, the abutment and counterweight block respectively cover the corresponding shear key. Through the setting of the shear key, the stability and reliability of the lateral load transmission inside the foundation structure can be further ensured. In this application, the shear reinforcement can be used as the shear key.

Preferably, after the step C1, a step C2 is also provided,

Step C2, coating the anti-adhesion layer: after the inner liner in the step C1 is hardened, coat the lower end of the inner liner with an anti-adhesion layer.

Preferably, the anti-bonding layer is an asphalt layer.

By setting the anti-bonding layer, in this way, there is no vertical constraint between the foundation slab and the inner lining. When the foundation slab is subjected to the vertical load imposed by the arch bridge, the foundation slab will not pull the inner lining, thereby avoiding The pull of the vertical load on the support, in this way, avoids the risk of the support being pulled and damaged due to excessive vertical load, and further ensures the structural stability and reliability of the support; this setting can also avoid the risk of damage after the foundation slab is poured , under the action of temperature stress caused by concrete hydration heat, when the foundation plate shrinks, it will be pulled by the inner lining to cause cracks; on the other hand, it also makes the internal structure of the foundation of the application more clear and simple, which can greatly reduce the difficulty of design , but also reduces the possible uncertainties in the design work, and then also improves the stability and reliability of the design structure.

Preferably, in the step C, a step C3 is also set between the step C1 and the step C2, or after the step C2,

Step C3, grouting: grouting the bearing layer.

In the actual design work, according to the actual arch bridge structure and the actual geological conditions, it is possible to consider whether to grout the bearing layer, and further improve the bearing capacity of the bearing layer in turn. In the scheme of this application, due to the Existence, when the supporting member adopts an annular cylindrical structure, the outer periphery of the force-bearing layer is surrounded by the supporting member, which can avoid the occurrence of the pulp running problem.

Preferably, after the step F, a step G is also provided,

Step G, foundation pit backfilling: After the abutment in step E and the counterweight in step F are hardened, backfill the foundation pit. Fill the remaining space in the foundation pit by backfilling. On the one hand, it makes the ground at the foundation level and facilitates subsequent construction; In the actual support process, each component can share the load on the foundation, especially for the arch bridge structure, the lateral load-bearing capacity of each component inside the foundation is greatly enhanced by the support, so that the bearing layer is further reduced. Lateral bearing capacity requirements.

Compared with prior art, the beneficial effect of the present invention:

In the construction method of the present application, by excavating the trench, the lower part of the trench is located in the bearing layer, and the support obtained by pouring is embedded in the bearing layer, so that the bearing capacity of the bearing layer is improved. In this way, for the same supporting strength, The load-bearing capacity requirements for the bearing layer can be reduced. On the one hand, the excavation depth can be reduced, so that the foundation structure of the application can be applied to the geological conditions with thick covering layers; on the other hand, for the same bearing layer , adopting the basic structure of the present application can greatly improve the bearing capacity of the foundation, so that the basic structure of the present application can be applied to the foundation of long-span arch bridges.

Description of drawings:

Fig. 1 is the structural representation of the basic section of the present application;

Fig. 2 is a top view schematic diagram after the counterweight is set on the foundation plate when the horizontal section of the support is circular,

Marked in the picture: 1-arch seat, 2-bearing layer, 3-support, 4-foundation plate, 5-shear key, 6-backfill, 7-counterweight, 8-anti-adhesion layer, 9 - Lining.

Detailed ways

The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

Embodiment 1, as shown in Figures 1 and 2:

A long-span arch bridge foundation, including an abutment 1 and a bearing layer 2 for supporting the abutment 1, and also includes a support 3, which is arranged on the periphery of the bearing layer 2, the The supporting member 3 is used to support the bearing layer 2 in the lateral direction.

The basic structure of the present application is provided with the support member 3 for supporting the force-bearing layer 2 in the lateral direction, thereby greatly improving the lateral load-bearing capacity of the foundation of the application. The size of the support member 3 is based on the actual construction. Determine the magnitude of the lateral load on layer 2. Due to the setting of the support member 3, the lateral bearing capacity of the foundation structure is improved, thereby reducing the requirement for the bearing capacity of the bearing layer 2. Therefore, in actual construction, the excavation depth of the foundation can be reduced, and the construction cost and shortening time can be reduced. construction period, and can be applied to more geological conditions; on the other hand, due to the strengthening of the lateral bearing capacity of the foundation bearing layer 2, the use of the basic structure of the application can improve the greater supporting capacity, and then can be applied to Large-span, even super-long-span arch bridge construction.

On the basis of the above structure, as a more excellent embodiment, the support member 3 is arranged vertically. Support member 3 is vertically arranged, can effectively avoid the vertical load that support member 3 is subjected to, so, on the one hand: make support member 3 only bear the lateral load of horizontal method, avoid vertical load excessive and damage support member 3, guarantee The structural safety of the support member 3; on the other hand, it makes the force of the support member 3 more clear, facilitates the structural design, reduces uncertain factors in the design process, and thus improves the reliability and safety of the structural design.

As a more excellent embodiment, the support member 3 is a hollow cylindrical structure with both ends open, and the inner wall of the support member 3 cooperates with the side wall of the force-bearing layer 2 . Setting the support member 3 as a hollow cylindrical structure, on the one hand, makes the support member 3 coordinate with each other in the circumferential direction, and acts as a hoop for the internal force-bearing layer 2, which can significantly improve the geological conditions. The bearing capacity, deformation modulus and seismic performance of the bearing layer can be improved to improve the lateral load bearing capacity of the support 3; on the other hand, when the bearing capacity of the bearing layer 2 is poor, the bearing layer 2 can be grouted, and During grouting construction, the support member 3 can also effectively prevent grout from running out, save construction cost and shorten construction period, and at the same time improve the quality of grouting and ensure the structural reliability of the bearing layer 2 .

As a more excellent embodiment, the horizontal cross-sectional shape of the support member 3 is a circle, an oval ring or a square ring.

As a more excellent implementation, the support 3 is a continuous wall. The continuous wall structure is adopted. In actual construction, trenches are first excavated on the ground corresponding to the continuous wall and reinforced concrete is poured. When the continuous wall reaches the design strength, the soil in the wall is excavated. , Due to the support and closure of the diaphragm wall, there is no need to set up internal support and water sealing structures during the excavation process, so the excavation process is also simplified and construction costs are saved.

As a more excellent embodiment, the force-bearing layer 2 is also provided with a base plate 4, and the matching area between the base plate 4 and the force-bearing layer 2 is larger than the bottom area of the abutment 1, and the The abutment 1 is arranged on the base plate 4 . By setting the base plate 4, on the one hand, the force-bearing area of the force-bearing layer 2 is enlarged to reduce the vertical stress, and on the other hand, the force of the force-bearing layer 2 is more uniform, thereby further reducing the force-bearing force Layer 2 load carrying capacity requirements.

As a more excellent embodiment, the foundation plate 4 is a concrete structure poured on the bearing layer 2 . The base plate 4 is formed by pouring. During the pouring process, part of the mixture flows into the gap between the bearing layers 2. On the one hand, it plays a certain role in strengthening the bearing layer 2. On the other hand, it also improves This ensures the reliability of the connection between the foundation plate 4 and the bearing layer 2, and ensures the reliable transmission of lateral loads and vertical loads.

As a more excellent embodiment, the upper edge of the support member 3 continues to extend upward after exceeding the upper edge of the bearing layer 2 , and covers the side wall of the base plate 4 . In this way, while the support member 3 strengthens the lateral load-bearing capacity of the force-bearing layer 2, it also strengthens the lateral load-bearing capacity of the base plate 4, and, because the base plate 4 shares the lateral load, it also further reduces The transverse load suffered by the force-bearing layer 2 is reduced, and further reduces the requirement on the lateral load-bearing capacity of the force-bearing layer 2 .

As a more excellent embodiment, several shear keys 5 are connected between the base plate 4 and the abutment 1 . Through the setting of the shear key 5, the transmission of the lateral load between the abutment 1 and the foundation plate 4 is further ensured, thereby ensuring the reliable transmission of the lateral load by the foundation structure of the present application.

As a more excellent embodiment, the excavated space on the foundation plate 4 is also filled with backfill soil 6 .

As a more excellent embodiment, a counterweight 7 is further arranged on the base plate 4 , and the counterweight 7 is used to adjust the stress distribution of the force-bearing layer 2 . According to the stress distribution in the actual design structure, the counterweight 7 is set to adjust the stress. In this way, the adaptability of the basic structure of the application to different geological conditions can be further improved, and the force of the bearing layer 2 can also be further adjusted conveniently. optimization, thereby further reducing the requirements on the geological performance of the bearing layer 2.

As a more excellent embodiment, the weight, shape and position of the counterweight 7 ensure that the stress of the force-bearing layer 2 on the same horizontal plane is consistent. In this way, the forces on the positions of the force-bearing layer 2 and the base plate 4 are relatively uniform, avoiding the occurrence of large local stresses, ensuring that the components can fully exert their mechanical properties, and reducing the uneven force caused by the force-bearing layer 2 risk of subsidence.

As a more excellent embodiment, the side wall of the counterweight 7 is attached to the side wall of the abutment 1 . The side walls of the counterweight 7 and the side walls of the abutment 1 fit together, so that the counterweight 7 can also transmit the lateral load suffered by the abutment 1 while playing the role of counterweight, further reducing the holding time. The lateral load received by the force layer 2 further reduces the requirement on the lateral bearing capacity of the force layer 2 .

As a more excellent embodiment, several shear keys 5 are connected between the counterweight 7 and the base plate 4 . The base plate 4 can share the lateral load on the counterweight 7 , on the other hand, it also ensures the stability of the counterweight 7 and prevents the counterweight 7 from shifting.

As a more excellent implementation, the shear key 5 is a steel bar segment.

As a more excellent embodiment, the upper edge of the support member 3 continues to extend upwards to the ground after exceeding the upper edge of the base plate 4 . In this way, the lower end of the support member 3 is located in the bearing layer 2, and then extends upward to the ground. On the one hand, it is further convenient for excavation construction; The lateral load can be transmitted more reliably, thereby ensuring the stability of the foundation structure and reducing the requirement for the lateral bearing capacity of the bearing layer 2.

As a more excellent embodiment, an inner liner 9 is also provided on the inner wall of the support member 3 above the base plate 4, the inner liner 9 is hollow and cylindrical, and the outer wall of the inner liner 9 is in the same shape as the The inner walls of the support 3 are matched. By setting the lining 9, the support strength of the support 3 is increased, and the structural reliability of the support 3 is improved.

As a more excellent implementation, the inner lining 9 is a reinforced concrete structure.

As a more excellent embodiment, the lower end of the inner liner 9 is arranged on the base plate 4, and a barrier between the lower end of the inner liner 9 and the base plate 4 is provided to prevent the inner liner 9 from contacting the base plate. 4 connected anti-adhesive layers 8 .

As a more excellent embodiment, the anti-adhesion layer 8 is an asphalt layer coated on the lower end of the inner liner 9 and/or the base plate 4 .

As another excellent embodiment, the lower end of the inner liner 9 and the base plate 4 are clearance fit.

In the above scheme of the present application, an anti-adhesion layer 8 is set between the lower end of the inner liner 9 and the base plate 4, or a clearance fit is set between the lower end of the inner liner 9 and the base plate 4. In this way, the base plate 4 and the inner lining 9, there is no vertical constraint. When the foundation plate 4 is subjected to the vertical load imposed by the arch bridge, the foundation plate 4 will not pull the inner lining 9, thus avoiding the pulling of the support 3 by the vertical load. In this way, the danger of the support member 3 being pulled and damaged due to excessive vertical load is avoided, and the structural stability and reliability of the support member 3 are further ensured; such setting can also avoid the concrete hydration after the foundation plate 4 is poured. Under the action of temperature stress caused by heat, when the base plate 4 shrinks, it is pulled by the inner lining 9 to generate cracks; The uncertain factors that may exist in the design work are reduced, and the stability and reliability of the design structure are also improved.

Embodiment 2: As shown in Figures 1 and 2:

A construction method applicable to the foundation of a long-span arch bridge, comprising the following steps:

A, trench excavation: excavate a trench on the ground corresponding to the arch bridge foundation support 3, and the lower part of the trench is located in the bearing layer 2;

B. Pouring support 3: pour concrete in the trench excavated in step A, and obtain support 3 after hardening;

C. Excavation of the foundation pit: Excavate the soil layer above the bearing layer 2 until the bearing layer 2;

D, pouring base plate 4: pouring concrete in the foundation pit formed in step C to obtain base plate 4;

E. Pouring the abutment 1: After the base plate 4 in step D is hardened, pour the abutment 1 on the base plate 4.

In the construction method of the present application, by excavating the trench, the lower part of the trench is located in the bearing layer 2, and the support member 3 obtained by pouring is embedded in the bearing layer 2, so that the bearing capacity of the bearing layer 2 is improved. In this way, for the same The supporting strength can reduce the load-bearing capacity requirements of the bearing layer 2. On the one hand, the excavation depth can be reduced, so that the foundation structure of the present application can be applied to geological conditions with thicker covering layers; on the other hand, for the same As far as the bearing layer 2 is concerned, the foundation structure of the application can greatly improve the bearing capacity of the foundation, so that the foundation structure of the application can be applied to the foundation of long-span arch bridges.

As a more excellent embodiment, step F is also provided after step E,

Step F, setting the counterweight 7: pouring the counterweight 7 on the base plate 4, so that the force exerted by the base plate 4 on the force-bearing layer 2 is uniform. When carrying out the structural design of the foundation, that is to determine the size and position parameters of the counterweight 7, through the counterweight 7, the force-bearing layer 2 is subjected to relatively uniform pressure from the foundation plate 4, maintaining the stability and reliability of the foundation structure .

As a more excellent embodiment, the abutment 1 in the step E and the counterweight 7 in the step F are poured at the same time. Simultaneous pouring, on the one hand, can save the construction process and reduce the construction cost; on the other hand, it can also make the connection between the abutment 1 and the counterweight 7 tighter, and ensure the load between the abutment 1 and the counterweight 7 delivery stability.

As a more excellent implementation, step A1 is also provided between steps A and B,

Step A1, setting up reinforcement bars: arrange reinforcement bars or reinforcement cages in the trenches excavated in step A, so that the support member 3 obtained by pouring in step B is a reinforced concrete structure. Setting the support member 3 as a reinforced concrete structure further improves the structural strength of the support member 3 and further enhances the strengthening effect of the support member 3 on the lateral bearing capacity of the foundation.

As a more excellent embodiment, the step C also includes step C1,

Step C1, setting the lining 9: pouring the lining 9 on the inner wall of the support 3 above the foundation plate 4.

Through the arrangement of the lining 9, the structural strength of the support member 3 is further strengthened, and the stability and reliability of the basic structure are further improved.

As a more excellent implementation, in the step C1, the pouring of the inner lining 9 is carried out by reverse method.

As a more excellent implementation, in the step D, when pouring the foundation plate 4, a number of shear keys 5 are vertically arranged at the positions corresponding to the abutment 1 and the counterweight 7, and the shear keys 5 The lower half of the force key 5 is located in the base plate 4, and the upper half of the shear key 5 protrudes from the base plate 4. When performing steps E and F, the abutment 1 and the counterweight 7. Cover the respective corresponding shear keys 5. Through the setting of the shear key 5 , the stability and reliability of the lateral load transmission inside the foundation structure can be further ensured. In this application, the shear reinforcement can be used as the shear key 5 .

As a more excellent implementation, after the step C1, there is also a step C2,

Step C2, coating the anti-adhesive layer 8: after the inner liner 9 in the step C1 is hardened, coat the lower end of the inner liner 9 with an anti-adhesive layer 8.

As a more excellent embodiment, the anti-adhesion layer 8 is an asphalt layer.

By setting the anti-bonding layer 8, in this way, there is no vertical constraint between the base plate 4 and the inner lining 9, and when the base plate 4 is subjected to the vertical load imposed by the arch bridge, the base plate 4 will not pull the inner lining 9. Lining 9, thereby avoiding the pulling of the support member 3 by the vertical load, thus avoiding the danger of the support member 3 being pulled and damaged due to excessive vertical load, and further ensuring the structural stability and reliability of the support member 3; setting, it can also avoid that after the foundation slab 4 is poured, under the temperature stress caused by the heat of concrete hydration, when the foundation slab 4 shrinks, it will be pulled by the lining 9 to cause cracks; on the other hand, it also makes the foundation of the application The structural force is clearer and simpler, which can greatly reduce the difficulty of design, and also reduce the possible uncertainties in the design work, thereby improving the stability and reliability of the design structure.

As a more excellent implementation, in the step C, there is also a step C3 between the step C1 and the step C2, or after the step C2,

Step C3, grouting: grouting the bearing layer 2 .

In the actual design work, according to the actual arch bridge structure and actual geological conditions, it is possible to consider whether to grout the bearing layer 2, and further improve the bearing capacity of the bearing layer 2 in turn. In the scheme of this application, due to the support Due to the existence of the support member 3, when the support member 3 adopts an annular cylindrical structure, the periphery of the force-bearing layer 2 is surrounded by the support member 3, which can avoid the occurrence of the pulp running problem.

As a more excellent embodiment, after the step F, a step G is also provided,

Step G, foundation pit backfilling: After the abutment 1 in step E and the counterweight 7 in step F are hardened, backfill the foundation pit. The remaining space in the foundation pit is filled with backfilling soil 6. On the one hand, the ground at the foundation is leveled to facilitate subsequent construction; on the other hand, the filling of backfilling soil 6 coordinates the internal structural parts of the foundation , in the actual support process, each component can share the load on the foundation, especially for the arch bridge structure, the lateral load-bearing capacity of each component inside the foundation is greatly strengthened by the support 3, thus further reducing the load on the foundation. Requirements for the lateral bearing capacity of the bearing layer 2.

The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the specification has described the present invention in detail with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned specific implementation methods, so Any modification or equivalent replacement of the present invention; and all technical solutions and improvements that do not deviate from the spirit and scope of the invention shall be covered by the claims of the present invention.

Claims (10)

1. A kind of 1. construction method suitable for large span arch bridge basis, it is characterised in that：

   Comprise the steps：

   A, groove is excavated：Groove is being excavated corresponding to arch bridge base support member on ground, the lower trench point is located at supporting course In；

   B, support member is poured：The casting concrete in the groove that step A is excavated, be supported part after hardening；

   C, excavation pit：Soil layer above supporting course excavates, until supporting course；

   D, soleplate is poured：Step C-shaped into foundation ditch in casting concrete obtain soleplate；

   E, skewback is poured：After step D soleplate hardening, skewback is poured on soleplate.
2. 2. construction method according to claim 1, it is characterised in that：Step F is additionally provided with after the step E,

   Step F, balancing weight is set：Balancing weight is poured on the soleplate, makes force of the soleplate to the supporting course Uniformly.
3. 3. construction method according to claim 2, it is characterised in that：The skewback of the step E and step F balancing weight are same Shi Jinhang is poured.
4. 4. according to the construction method described in claim 1-3 any one, it is characterised in that：It is additionally provided between step A and B Step A1,

   Step A1, reinforcing bar is set：Reinforcing bar or steel reinforcement cage are arranged in the groove that step A is excavated, step B is poured obtained branch Support member is reinforced concrete structure.
5. 5. according to the construction method described in claim 1-3 any one, it is characterised in that：In the step C, also include step Rapid C1,

   Step C1, liner is set：Liner is poured on support member inwall above the soleplate.
6. 6. according to the construction method described in claim 1-3 any one, it is characterised in that：In the step D, basis is being carried out When plate pours, some shear connectors, the lower half of the shear connector are also vertically arranged with position corresponding to skewback and balancing weight Divide in the soleplate, the top half of the shear connector stretches out the soleplate, when carrying out step E and F, the arch Each self-corresponding shear connector is coated on interior by seat and balancing weight.
7. 7. construction method according to claim 5, it is characterised in that：After the step C1, step C2 is additionally provided with,

   Step C2, anti-adhesive linkage is coated：After the liner hardening of the step C1, anti-adhesive linkage is coated in liner lower end.
8. 8. construction method according to claim 7, it is characterised in that：The anti-adhesive linkage is bitumen layer.
9. 9. construction method according to claim 7, it is characterised in that：It is characterized in that：In the step C, in the step Suddenly between C1 and step C2, or step C3 is additionally provided with after the step C2,

   Step C3, slip casting：Slip casting is carried out to supporting course.
10. 10. the construction method according to Claims 2 or 3, after the step F, step G is additionally provided with,

    Step G, foundation ditch backfills：After the balancing weight hardening of step E skewback and step F, foundation ditch is backfilled.