CN107090804B - A kind of flexible net debris flow dam and its construction method - Google Patents

Abstract

The invention discloses a debris flow sand retaining dam with a flexible mesh and a construction method thereof. The sand retaining dam includes several concrete buttresses for dividing a wide mud and rock flow channel into a number of suitable width ranges for the flexible mesh, and the concrete buttresses are stepped. Rise up and set in sequence from bottom to top as the first step, the second step and the third step; each concrete buttress is provided with a lateral tooth sill in the longitudinal middle of the side with the adjacent concrete buttress; the concrete The bottom of the pier is provided with a horizontal cap, and the bottom of the horizontal cap is provided with anti-slip tooth sills and several steel pipe piles. The structure of the invention is simple in construction and saves investment, and can be used for blocking mud-rock flows in large and wide ditches. When the debris flow comes, the debris flow is divided into multiple strands by the concrete pier, and then accumulates under the action of the flexible net barrier between the adjacent first steps. Accumulate under the action to realize the control of debris flow.

Description

A flexible net debris flow sand retaining dam and its construction method

technical field

The invention relates to the field of mud-rock flow ditch control engineering, in particular to a flexible mesh mud-rock flow sand retaining dam and a construction method thereof.

Background technique

Debris flow refers to a special torrent carrying a large amount of sediment and stones due to landslides caused by heavy rain, snowstorm or other natural disasters in mountainous areas or other areas with deep valleys and steep terrain. Debris flow has the characteristics of suddenness, fast flow rate, large flow rate, large material capacity and strong destructive force. Debris flows often destroy highways, railways and other transportation facilities and even villages and towns, causing huge losses.

Debris flow is a torrent formed by heavy rain and floods after saturation and dilution of soft soil mountains containing sand and rocks. Its area, volume and flow are large, while landslides are areas of small areas of diluted soil mountains. Typical debris flows are caused by suspended It is composed of viscous mud rich in silt and clay with coarse solid clastics. Under appropriate terrain conditions, a large amount of water soaks the solid accumulations in the flowing water hillside or ditch bed, reducing its stability, and the solid accumulations saturated with water move under their own gravity, forming a debris flow. Debris flow is a disastrous geological phenomenon. Mudslides usually erupt suddenly and violently, and can carry huge rocks. Because of its high speed and powerful energy, it is extremely destructive. Therefore, it is self-evidently important to control and prevent debris flow.

In debris flow channels, concrete sand retaining dams are generally used, and discharge holes are set on the dam body and overflow ports are set on the dam crest. On the one hand, large-volume concrete sand check dams have higher requirements for the foundation of valley slopes, and the excavation of foundation pits is large, which increases the amount of solid matter; on the other hand, the foundation of concrete dams is prone to deformation, and the construction period is long and the cost is high. Therefore, it is necessary to design a simple and practical sand retaining dam structure to control the debris flow channel.

Debris flow flexible mesh protection structure is widely used in debris flow control projects in western countries. It has the characteristics of saving investment, good landscape and easy installation. However, because the flexible net is easy to deform and its structure is unstable, the width of its use is limited, and the strength of the flexible net also limits the blocking height. Therefore, how to improve the flexible net to expand its application range and apply the flexible net to wide debris flow channels has certain reference value for the selection of debris flow prevention and control projects.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a flexible mesh debris flow sand control dam and its construction method. The flexible mesh is applied to the debris flow control project. The structure design is simple and the construction is convenient without causing damage to the original channel bed A large amount of damage has provided a good solution for the control of debris flow.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

Provided is a flexible mesh debris flow sand retaining dam, which includes several concrete buttresses for dividing the debris flow channel into suitable for the width range of the flexible mesh. The concrete buttresses rise in a step-like manner, and are arranged as the first step from bottom to top , the second step and the third step; the two sides of the middle part of the first step between two adjacent concrete piers are provided with lateral tooth sills to make the concrete pier more stable during the accumulation of debris flow; A flexible net is evenly distributed between the first step, the second step and the third step of each concrete pier;

The bottom of the concrete pier is provided with a horizontal cap, and the downstream bottom of the horizontal cap is provided with an anti-slip tooth sill; the upstream bottom of the horizontal cap is provided with several steel pipe piles.

Further, the first step, the second step and the third step of the concrete pier are provided with several reinforcements penetrating from the bottom to the top; the reinforcements include several steel bars with a diameter of 20mm and several steel bars with a diameter of 12mm. Stirrups, the distance between two adjacent steel bars is 20cm, and the distance between two adjacent stirrups is 40cm.

Further, the flexible nets between two adjacent first and second steps are all arranged on the downstream side, and the flexible nets between two adjacent third steps are all arranged on the upstream side.

Further, the transverse length of each horizontal platform is 8m, the longitudinal length is 13m, and the height is 2m.

Further, each anti-skid sill is set in a trapezoidal shape, the longitudinal lengths of the two bottom surfaces of the anti-slip sill are 1.5m and 2.5m respectively, the height of the anti-slip sill is 2m, and the transverse length is 8m.

Furthermore, a number of steel pipe piles are arranged in a quincunx shape, and each steel pipe pile is filled with cement slurry; the distance between two adjacent steel pipe piles is 0.8m, the length of each steel pipe pile is 10m, and the nominal diameter is 10cm, wall thickness 4mm; each steel pipe pile is provided with a number of openings with a distance of 50cm and a diameter of 10mm.

Further, the distance between each group of adjacent concrete piers is 20m; the first step, the second step and the third step of each concrete pier are provided with several reinforcements from the bottom to the top.

Further, the longitudinal length of each first step is 4.5m, the height is 5m, and the transverse length is 5m; the longitudinal length of each second step is 1m, the height is 5m, and the transverse length is 5m; each third The vertical length of the steps is 3.5 meters, the height is 5 meters, and the horizontal length is 5 meters;

The transverse length of reinforcement in the first step is 5m, the longitudinal length is 2m, and the height is 5m; the transverse length of the reinforcement in the second step is 5m, the longitudinal length is 1.5m, and the height is 10m; The transverse length of reinforcement is 5m, the longitudinal length is 1.5m, and the height is 15m.

Further, each lateral sill is set in a trapezoidal shape, the longitudinal lengths of the two bottom surfaces of the lateral sills are 1m and 1.5m respectively, and the transverse length is 1.5m.

A construction method for a flexible net debris flow sand dam is provided, which includes the following steps:

S1. Set a number of openings with a distance of 10 cm and a diameter of 1 cm on several steel pipe piles (3) with a length of 10 m and a diameter of 10 cm, and place the steel pipe piles (3) in a plum blossom shape with a distance of 0.8 m in pairs 2-3m deep into the base, and fill each steel pipe pile (3) with cement slurry;

S2. Pouring horizontal caps and anti-skid sills on the steel pipe piles, and setting reinforcement on the horizontal caps according to the specifications of 20cm between steel bars and 40cm between stirrups;

S3. After the horizontal bearing platform is solidified to the design strength, pour the first step, the second step and the third step on the horizontal bearing platform from bottom to top to form a concrete support pier, and place two adjacent concrete supports The two sides of the middle part of the first step between the piers are provided with trapezoidal lateral sills with longitudinal lengths of 1m and 1.5m and transverse lengths of 1.5m;

S4. Arranging a layer of flexible net between two adjacent first steps, two adjacent second steps and two adjacent third steps.

The beneficial effects of the present invention are:

1. The present invention improves the continuous sand control dam body into several regular buttress structures, and arranges a flexible protective net between adjacent buttresses to become a water-permeable body containing a filtration system. Just can reduce the amount of excavation to valley, ditch foundation when using the above-mentioned sand retaining dam.

2. By arranging concrete buttresses, the interval between two adjacent concrete buttresses is smaller than the use range of the width of a single debris flow flexible net, and the deployment of flexible nets in the height direction rises in steps, breaking through the limit of the use of a single flexible net width. The strength of the flexible net meets the actual needs. The structure of the invention is simple in construction and saves investment, and can be used for blocking mud-rock flows in large and wide ditches. When the debris flow comes, the debris flow is divided into multiple strands by the concrete pier, and then accumulates under the action of the flexible net barrier between the adjacent first steps. Accumulate under the action to realize the control of debris flow.

3. The concrete pier of the present invention has relatively low requirements on valleys and channel foundations, and will not cause a lot of damage to the original channel foundations, and the construction period is short and investment is saved. In addition, the flexible net with filtration system between two adjacent piers not only meets the requirements of blocking solid matter, but also can permeate water and flow. The structure design is simple and reduces engineering risks. It is a safe and reliable debris flow channel Treatment engineering, especially suitable for blocking debris flow in large and wide ditches.

4. The anti-slip tooth sill can limit the displacement of the reinforced concrete pier along the direction of the channel.

5. The lateral sill makes the reinforced concrete pier more stable laterally during the accumulation of debris flow.

6. Reinforcement in concrete can increase the strength and rigidity of concrete. The main function of the longitudinally stressed steel bar is to bear the tension generated in the beam under the action of external force. The main function of erecting steel bars is to fix the stirrup to ensure its correct position and form a steel skeleton with a certain rigidity. At the same time, the erecting steel bars can also withstand the stress caused by temperature changes and shrinkage of concrete to prevent cracks. The main function of the stirrup is to bear the shear force. In addition, stirrups and other steel bars form a well-integrated space skeleton by binding or welding.

7. The bearing support points arranged in a quincunx shape are distributed in a polygonal shape, so the stability of the pile foundation is good, the uneven settlement is small, and it will not tilt or crack over time.

8. A number of openings set on the steel pipe pile facilitate the consolidation of the cement slurry with the surrounding bottom layer and improve the fixing effect of the steel pipe pile.

9. The steel pipe pile can prevent the soil layer at the lower part of the horizontal cap from being scoured, improving the durability and stability of the present invention.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of setting three concrete buttresses according to the present invention.

Among them: 1. Concrete buttress; 2. Horizontal cap; 3. Steel pipe pile; 4. Anti-skid sill; 5. Flexible mesh; 6. Lateral sill; 7. The first step; 8. The second level ladder; 9, the third ladder.

Detailed ways

The specific embodiments of the present invention are described below so that those skilled in the art can understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

As shown in Figure 1 (the present invention has continuity, only draw 3 horizontal bearing platforms 2 and other corresponding parts among the figure, if need horizontal bearing platform 2 be set to other numbers, only need on the basis of Fig. 1 Just add horizontal caps 2 and other corresponding components to both sides), the flexible net debris flow sand retaining dam includes several concrete buttresses 1 for dividing the debris flow channel into the width range of the flexible net 5, and the concrete buttresses 1 It rises in the form of steps, and is set in sequence from bottom to top as the first step 7, the second step 8 and the third step 9; the first step 7 between two adjacent concrete piers 1 is set on both sides of the middle There are lateral tooth sills 6 that make the concrete buttress 1 more stable during the accumulation of debris flow; the first step 7, the second step 8 and the third step 9 of two adjacent concrete buttresses 1 are all laid out There is a flexible net 5;

The bottom of the concrete pier 1 is provided with a horizontal cap 2 , and the downstream bottom of the horizontal cap 2 is provided with an anti-skid sill 4 ; the upstream bottom of the horizontal cap 2 is provided with several steel pipe piles 3 .

The first step 7, the second step 8 and the third step 9 of the concrete pier 1 are provided with a number of reinforcements penetrating from the bottom to the top.

The flexible nets 5 between two adjacent first steps 7 and the second steps 8 are arranged on the downstream side, and the flexible nets 5 between two adjacent third steps 9 are arranged on the upstream side.

The transverse length of each horizontal platform 2 is 8m, the longitudinal length is 13m, and the height is 2m.

Each anti-slip tooth sill 4 is all set to trapezoidal, the longitudinal length of the two bottom surfaces of the anti-slip tooth sill 4 is 1.5m and 2.5m respectively, the height of the anti-slip tooth sill 4 is 2m, and the transverse length is 8m.

Several steel pipe piles 3 are arranged in a quincunx shape, and each steel pipe pile 3 is filled with cement slurry; the distance between two adjacent steel pipe piles 3 is 0.8m, the length of each steel pipe pile 3 is 10m, and the nominal diameter 10cm, wall thickness 4mm; each steel pipe pile 3 is provided with a number of openings with a pitch of 50cm and a diameter of 10mm.

The distance between each group of adjacent concrete pier 1 is 20m; the first step 7, the second step 8 and the third step 9 of each concrete pier 1 are provided with several reinforcements from the bottom to the top.

The longitudinal length of each first-order ladder 7 is 4.5m, the height is 5m, and the transverse length is 5m; the longitudinal length of each second-order ladder 8 is 1m, the height is 5m, and the transverse length is 5m; each third-level The vertical length of the ladder 9 is 3.5 meters, the height is 5 m, and the horizontal length is 5 m.

The reinforcements are set in three groups and are respectively arranged in the first step 7, the second step 8 and the third step 9; the horizontal length of the reinforcement in the first step 7 is 5m, the longitudinal length is 2m, and the height is 5m; the horizontal length of the reinforcement in the second step 8 is 5m, the longitudinal length is 1.5m, and the height is 10m (the reinforcement in the second step 8 has partially entered the third step 9); the third step 9. The horizontal length of the internal reinforcement is 5m, the longitudinal length is 1.5m, and the height is 15m; the reinforcement includes several secondary steel bars with a diameter of 20mm and several secondary stirrups with a diameter of 12mm, and the distance between two adjacent steel bars is 20cm, and the distance between two adjacent stirrups is 40cm.

Each lateral tooth sill 6 is arranged in a trapezoidal shape, the longitudinal lengths of the two bottom surfaces of the lateral tooth sills 6 are respectively 1m and 1.5m, and the transverse length is 1.5m.

The construction method of the flexible net debris flow sand retaining dam comprises the following steps:

S1. Excavation of the base: design and excavate the foundation pit to the required elevation according to the base stress of the proposed sand control dam and the bearing capacity of the natural foundation of the dam foundation;

S2. Layout of steel pipe piles 3: Combined with the topographical conditions of the sand retaining dam, the steel pipe piles 3 with a diameter of 10cm are driven into 2-3 meters below the base, arranged in a plum blossom shape with a spacing of 0.8m. Cement slurry is injected into the steel pipe pile 3, so that the steel pipe and the cement slurry in the pipe are integrated to form a composite steel pipe pile foundation;

S3. Arrangement of the anti-slip tooth sill 4: the anti-slip tooth sill 4 is arranged at the slope foot of the horizontal bearing platform 2, the depth is 2-5 meters, and the length and width are consistent with the size of the horizontal bearing platform 2;

S4. Construction of the reinforced concrete horizontal bearing platform 2: the construction of the horizontal bearing platform 2 shall be firmly connected with the steel pipe pile 3 and the anti-skid tooth sill 4, and the corresponding concrete label and steel bar specification shall be selected according to the design requirements;

S5. Construction of reinforced concrete pier 1: According to the engineering survey report, determine the soil mechanical parameters such as friction angle and cohesion in the soil, and consider the stress state of the sand control dam under different operating conditions to carry out the construction of the sand control dam support pier Calculation of anti-skid and anti-overturning stability. Based on the horizontal bearing platform 2, when the horizontal bearing platform 2 reaches the design strength, start to construct the buttress ladder layer by layer from bottom to top until the construction of the entire buttress is completed. The concrete label is C20, and the main reinforcement is 20mm in diameter. The first-grade steel bar, the steel bar spacing is 20cm, and the stirrup adopts 12mm second-level steel bar, the spacing is 40cm;

S6. Construction of the lateral tooth sill 6: while constructing the bottom step of the pier, the construction of the trapezoidal lateral tooth sill 6 is carried out on the outer surface of the buttress. The longitudinal lengths of the two bottom surfaces of the lateral tooth sill 6 are 1m respectively and 1.5m, the transverse length is 1.5m;

S7. Arrangement of the flexible net 5: a plurality of flexible protective nets are laid between two adjacent piers, and the flexible protective nets are arranged upstream in the horizontal direction as the height increases. The downstream and middle part of the flexible protective net is arranged on the downstream side of the first and second steps of the buttress, and the most upstream flexible protective net is arranged on the upstream side of the third level of the buttress.

In one embodiment of the present invention, the number of layers of the flexible net 5 can be selected according to the scale of the debris flow, the depth of the channel, and the like.

In the present invention, by arranging concrete buttresses 1, the interval between two adjacent concrete buttresses 1 is smaller than the use range of the length of a single debris flow flexible net 5, and the arrangement of flexible nets 5 in the height direction rises in steps, so that the height of the existing flexible nets 5 conforms to Actual demand. The structure of the invention is simple in construction and saves investment, and can be used for blocking mud-rock flows in large and wide ditches. When the debris flow comes, the debris flow is divided into multiple strands by the concrete support pier 1, and then accumulates under the blocking effect of the flexible net 5 between the adjacent first steps 7. As the accumulation height exceeds the flexible net 5 in this section, the debris flow is successively higher. The horizontal flexible net 5 is piled up under the blocking effect to realize the control of debris flow.

Claims (10)

1. a kind of flexible net debris flow dam, it is characterised in that：Including it is several for mud-rock flow channel is divided into be suitble to it is soft Property net (5) width range concrete buttress (1), the concrete buttress (1) rises in stepped ramp type, and successively sets from the bottom to top It is set to first order ladder (7), second level ladder (8) and third level ladder (9)；Between the two neighboring concrete buttress (1) First order ladder (7) on both sides of the middle be provided with and keep the concrete buttress (1) more firm during Debris Flow Deposition Lateral notched sill (6)；First order ladder (7), second level ladder (8) and the third level rank of the two neighboring concrete buttress (1) The flexible net (5) are laid between terraced (9)；

The bottom of the concrete buttress (1) is provided with horizontal cushion cap (2), and horizontal cushion cap (2) downstream base portion is provided with anti- Slip teeth sill (4)；The upstream bottom of the horizontal cushion cap (2) is provided with several steel-pipe piles (3).

2. flexible net debris flow dam according to claim 1, it is characterised in that：The of the concrete buttress (1) Several arrangements of reinforcement that top is penetrated into from bottom are provided in step (7), second level ladder (8) and third level ladder (9)； The stirrup that the arrangement of reinforcement includes the reinforcing bar that several diameters are 20mm and several diameters are 12mm, the spacing of adjacent two reinforcing bars For 20cm, the spacing of adjacent two stirrups is 40cm.

3. flexible net debris flow dam according to claim 1, it is characterised in that：Two neighboring first order ladder (7) Flexible net (5) between second level ladder (8) is laid in downstream side, the flexibility between two neighboring third level ladder (9) Net (5) is laid in upstream side.

4. flexible net debris flow dam according to claim 1, it is characterised in that：Each horizontal cushion cap (2) Lateral length is 8m, longitudinal length 13m, is highly 2m.

5. flexible net debris flow dam according to claim 1, it is characterised in that：Each anti-skidding notched sill (4) is equal It is arranged to trapezoidal, the longitudinal length of anti-skidding (4) two bottom surface of notched sill is respectively 1.5m and 2.5m, and the height of anti-skidding notched sill (4) is 2m, Lateral length is 8m.

6. flexible net debris flow dam according to claim 1, it is characterised in that：Several steel-pipe pile (3) settings At quincunx, cement slurry is filled in the every steel-pipe pile (3)；The spacing of the adjacent steel-pipe pile (3) is 0.8m two-by-two, The length of the every steel-pipe pile (3) is 10m, nominal diameter 10cm, wall thickness 4mm；It is respectively provided on the every steel-pipe pile (3) There are several holes away from the aperture for being 10mm for 50cm, aperture.

7. flexible net debris flow dam according to claim 1, it is characterised in that：Every group of adjacent concrete buttress (1) Spacing be 20m.

8. flexible net debris flow dam according to claim 2, it is characterised in that：Each first order ladder (7) Longitudinal length be 4.5m, be highly 5m, lateral length 5m；The longitudinal length of each second level ladder (8) is 1m, high Degree is 5m, lateral length 5m；The longitudinal length of each third level ladder (9) is 3.5 meters, is highly 5m, lateral length For 5m；

The lateral length of the interior arrangement of reinforcement of the first order ladder (7) is 5m, longitudinal length 2m, is highly 5m；The second level rank The lateral length of terraced (8) interior arrangement of reinforcement is 5m, longitudinal length 1.5m, is highly 10m；The interior arrangement of reinforcement of the third level ladder (9) Lateral length is 5m, longitudinal length 1.5m, is highly 15m.

9. flexible net debris flow dam according to claim 1, it is characterised in that：Each lateral notched sill (6) is equal It is arranged to trapezoidal, the longitudinal length of lateral (6) two bottom surface of notched sill is respectively 1m and 1.5m, lateral length 1.5m.

10. a kind of construction method of flexible net debris flow dam, which is characterized in that include the following steps：

S1, it is arranged that several spacing are 10cm, diameter is 1cm's on the steel-pipe pile (3) that several length are 10m, diameter is 10cm Steel-pipe pile (3) is goed deep into substrate 2-3m in quincunx for the specification of 0.8m with spacing two-by-two by aperture, and to every steel-pipe pile (3) Interior filling concrete slurry；

S2, horizontal cushion cap (2) and anti-skidding notched sill (4) are poured on steel-pipe pile (3), and according to bar spacing 20cm, stirrup spacing Arrangement of reinforcement is arranged on horizontal cushion cap (2) in the specification of 40cm；

S3, in horizontal cushion cap (2), solidification to after design strength, successively pours first order rank on horizontal cushion cap (2) from the bottom to top Terraced (7), second level ladder (8) and third level ladder (9) are formed concrete buttress (1), and in two neighboring concrete buttress (1) between first order ladder (7) on both sides of the middle setting longitudinal length be respectively 1m and 1.5m, lateral length be 1.5m it is trapezoidal Lateral notched sill (6)；

S4, in two adjacent first order ladders (7), two adjacent second level ladders (8) and two adjacent third level ranks One layer of flexible net (5) is respectively arranged between terraced (9).