CN110055829B - Transient pore water pressure buffering method and device for railway subgrade - Google Patents

Abstract

The invention provides a transient pore water pressure buffering method for a railway roadbed, wherein a buffering device is arranged in the roadbed, the dynamic effective stress of the roadbed is borne and transferred through a rigid device, and the dynamic pore water pressure of the roadbed is buffered through a flexible device. The buffering method can give consideration to two processes of transient pore water pressure increase and dissipation, and radically solves the problems of subgrade slurry turning and mud pumping. The invention also provides a buffer device which comprises a rigid device and a flexible device, wherein the rigid device is internally provided with an inner cavity, the surface of the rigid device is provided with a water through hole communicated with the inner cavity, pore water enters or flows out of the inner cavity through the water through hole, and the flexible device is arranged in the inner cavity to realize that the flexible device generates elastic deformation according to the change of the pore water pressure. The buffering device guarantees the stability of the roadbed through the rigid device, the dynamic pore water pressure of the roadbed is buffered through the flexible device, and the flexible device is arranged in the inner cavity of the rigid device and can play a role in protecting the flexible device.

Description

A kind of railway subgrade transient pore water pressure buffering method and device

technical field

The invention relates to the technical field of railway roadbed, in particular to a method and device for buffering transient pore water pressure of railway roadbed.

Background technique

Aiming at the transient pore water pressure of railway subgrade, the traditional treatment method is mainly to prevent and control, that is, to reduce the transient pore water pressure of subgrade by strengthening the drainage and water resistance of subgrade water. The specific measures mainly include: on the one hand, Improve the permeability inside the subgrade and speed up the water discharge rate inside the subgrade; on the other hand, grouting in the subgrade disease area to cut off the infiltration of rainwater. For example, Chinese patent CN201710351724 discloses a method for controlling slab-type ballastless track railway subgrade churn and mud. The remediation method is to prevent water from infiltrating into the subgrade by grouting, so as to cut off the infiltration of rainwater.

The traditional method of dealing with the transient pore water pressure of railway subgrade is a passive treatment method, which requires high processing materials and procedures. Secondly, the passive treatment method also has many disadvantages:

First, in the drainage treatment, in order to ensure high stability, the subgrade must be mechanically compacted during construction, so the overall pore ratio of the subgrade is small and its own permeability is poor. In the case of continuous rainy weather or local heavy rainfall, it is difficult to discharge the water in the foundation bed in time.

Second, in the water-proof treatment, the dynamic pore water cannot pass through the grouting area by means of grouting, but its dynamic pressure still exists, and the dynamic pressure will be transmitted to the far area, so the grouting area must be large enough and the grouting area must be large enough. Evenly, in order to meet the management requirements. Secondly, the grouting layer itself must have good water resistance, and on the one hand, the grouting layer must overcome the cyclic extrusion and suction effects of dynamic pore water pressure; The pulp material requirements are high, and it is difficult to ensure its long-term strength. Once a certain area of the grouting layer is damaged, the damage will gradually spread to other areas under the action of dynamic pore water pressure.

In conclusion, a method and device for buffering transient pore water pressure of railway subgrade are urgently needed to solve the problems existing in the prior art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of transient pore water pressure buffering method of railway subgrade, and the specific technical scheme is as follows:

A method for buffering transient pore water pressure of a railway subgrade, comprising a buffer device, the buffer device includes a rigid device and a flexible device, the rigid device is provided with a cavity structure inside and at least one on the surface that communicates with the inner cavity is provided. a water passage hole, the flexible device is integrally arranged in the inner cavity of the rigid device;

The buffering method includes arranging the buffering device in the roadbed, carrying and transmitting the dynamic effective stress of the roadbed by the rigid device, and buffering the dynamic pore water pressure of the roadbed by the flexible device.

Preferably, in the above technical solutions, the number of the buffering devices is at least one piece, and multiple pieces of the buffering devices are arranged on the surface layer of the subgrade bed of the roadbed at an even interval, and the surrounding is filled with a sandstone layer.

Preferably in the above technical solutions, when the train arrives, the subgrade soil skeleton is subjected to the dynamic load of the train, the volume of the subgrade under the load is rapidly reduced, and the dynamic pore water enters the inner cavity of the rigid device through the water passage hole, which deforms the flexible device and makes the dynamic pore water. Pore water pressure is weakened to achieve the purpose of alleviating excess pore water pressure;

When the train leaves, the subgrade soil skeleton unloads the train dynamic load, and the volume of the subgrade unloading load position increases rapidly, forming a negative pore water pressure; under the action of the negative pore water pressure, the pore water in the inner cavity of the rigid device is sucked out to relieve the negative pressure. For the purpose of pore water pressure, the flexible device recovers its deformation in preparation for the next dynamic load action.

The invention also provides a buffering device for transient pore water pressure of railway subgrade, including a rigid device for carrying and transmitting dynamic effective stress of subgrade and a flexible device for buffering dynamic pore water pressure of subgrade. There is a cavity structure and at least one water-passing hole communicated with the inner cavity is arranged on the surface, and the pore water flows into or out of the inner cavity through the water-passing hole, and the flexible device is integrally arranged in the inner cavity of the rigid device and is The flexible device is elastically deformed by pore water pressure.

Preferably in the above technical solutions, the rigid device is a hollow spherical shell, and the flexible device is a hollow rubber balloon.

Preferably in the above technical solutions, the water passage holes are evenly distributed on the surface of the spherical shell.

Preferably in the above technical solutions, the outer diameter of the spherical shell is 6-8 cm, the thickness of the shell is 8-10 mm, and the diameter of the water passage hole is 4-5 mm.

Preferably in the above technical solutions, the air pressure inside the hollow rubber balloon is 15-20kPa.

Preferably in the above technical solutions, the material of the spherical shell is low carbon stainless steel or hard plastic.

Applying the technical scheme of the present invention has the following beneficial effects:

(1) For the transient pore water pressure of railway subgrade, the existing inventions are all passive control measures, mainly to isolate and drain the subgrade water, and the treatment effect is closely related to the actual moisture content of the subgrade. The method for buffering the transient pore water pressure of railway subgrade proposed by the invention is a new way of thinking that escapes the constraints of subgrade water; The dynamic effective stress of the subgrade ensures the overall stability of the subgrade, and the flexible device buffers the dynamic pore water pressure of the subgrade to weaken the pore water pressure, and solve the problem of mud and mud from the source, and the buffer method of the present invention is not affected by the water content of the subgrade. Therefore, whether it is continuous rainfall or heavy rainfall, the phenomenon of mud churn and mud can be prevented.

(2) The buffering method of the present invention can take into account the two processes of transient pore water pressure increase and dissipation. When pore water pressure increases, pore water and a small amount of fine soil particles enter the rigid device, and the pore water pressure is weakened by the flexible device to achieve relief. The purpose of exceeding the pore water pressure; when the pore water pressure dissipates, under the action of the negative pore water pressure, the pore water inside the rigid device and a small amount of small soil particles attached can be quickly sucked out to achieve the purpose of relieving the negative pore water pressure. At the same time, the flexible device is restored to its original state to prepare for the next buffering. The buffering method of the present invention can protect the roadbed and prevent the phenomenon of mud and mud.

(3) The buffer method of the present invention fills the sand and gravel layers around multiple buffer devices. The number of buffer devices can be set according to the actual situation (for example, the amount of precipitation in the area), and the buffer device and the sand and stone layers can form a In the buffer network, each buffer point cooperates with each other to share the impact force caused by the dynamic load of the train, with a large buffer capacity, and can realize all-round buffering.

(4) The buffer device of the present invention includes a rigid device for carrying and transmitting the dynamic effective stress of the roadbed and a flexible device for buffering the dynamic pore water pressure of the roadbed. The rigid device is provided with an inner cavity and a surface with an inner cavity. Connected water passage holes, through which pore water can flow into or out of the inner cavity, and the flexible device is arranged in the inner cavity to realize elastic deformation of the flexible device according to the change of pore water pressure; the flexible device is provided with Inside the rigid device, the flexible device can be well protected, the frontal impact of the soil skeleton on the flexible device can be avoided, and the service life of the flexible device can be prolonged.

(5) The buffer device of the present invention has a simple structure, readily available materials, and is easy to process and mass-produce. The construction process of the buffer device is similar to that of ordinary roadbed construction, and the construction difficulty is relatively small.

(6) The spherical shell of the buffer device of the present invention is made of low-carbon stainless steel or hard plastic, which has high strength and rigidity, as well as good corrosion resistance, and effectively ensures the service life of the buffer device.

(7) The internal air pressure of the hollow rubber balloon of the present invention is 15-20kPa, and the air pressure value is the static pore water pressure at the depth of the buffer device under the saturated state of the roadbed. Setting this air pressure value can well ensure the stability of the hollow rubber balloon. , to ensure that the hollow rubber balloon is deformed in time to relieve the pore water pressure when it is squeezed by pore water, and at the same time, it also ensures that the hollow rubber balloon is not squeezed and ruptured.

(8) The outer diameter of the spherical shell of the present invention is 6-8 cm, the shell thickness is 8-10 mm, and the diameter of the water hole is 4-5 mm. The spherical shell is small, easy to process and convenient for use in roadbed construction. A diameter of 4-5mm can ensure that pore water enters and flows out of the rigid device, and also prevents large particles of sand and gravel from entering the rigid device, causing the flexible device to fail to elastically deform normally, thereby affecting the efficacy of the buffer device.

In addition to the objects, features and advantages described above, the present invention has other objects, features and advantages. The present invention will be described in further detail below with reference to the drawings.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

Fig. 1 is the overall structure schematic diagram of the buffer device of the present invention;

FIG. 2 is a schematic structural diagram of the buffer device in FIG. 1 when part of the spherical shell is removed;

Fig. 3 is the application schematic diagram of the buffer device of the present invention;

Among them, 1. railway track, 2. sleepers, 3. ballast, 4. first sandstone layer, 5. second sandstone layer, 6. third sandstone layer, 7. buffer device, 7.1, spherical shell, 7.2. Water passage hole, 7.3. Hollow rubber balloon, 8. Foundation bed.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention may be implemented in many different ways as defined and covered by the claims.

Example 1:

Referring to Figures 1-2, a railway subgrade transient pore water pressure buffer device includes a rigid device for carrying and transmitting the dynamic effective stress of the subgrade and a flexible device for buffering the dynamic pore water pressure of the subgrade. The inner part of the rigid device There is a cavity structure and at least one water passage hole (the cavity structure is the inner cavity) communicated with the inner cavity is arranged on the surface, and the pore water flows into or out of the inner cavity through the water passage hole, and the flexible The device is integrally arranged in the inner cavity of the rigid device and the flexible device is elastically deformed by pore water pressure. That is, when the pore water pressure is greater than the deformation pressure value of the flexible device, the flexible device deforms, and when the pore water pressure is lower than the deformation pressure value of the flexible device, the flexible device returns to its original state.

The rigid device is a hollow spherical shell 7.1, and the flexible device is a hollow rubber balloon 7.3 (preferably, the hollow rubber balloon is the rubber balloon in the prior art), of course, a solid rubber ball can also be used. It can meet the deformation requirements. The water passage holes 7.2 are uniformly arranged on the surface of the spherical shell 7.1. The outer diameter of the spherical shell is 6-8 cm, the thickness of the shell is 8-10 mm, and the diameter of the water passage hole is 4-5 mm. The internal air pressure of the hollow rubber balloon 7.3 is 15-20 kPa, and the internal air pressure is the air pressure when the hollow rubber balloon is not working. Preferably, in this embodiment, the outer diameter of the spherical shell is 6 cm, the thickness of the shell is 8 mm, the diameter of the water passage hole is 4 mm, and the air pressure of the hollow rubber balloon is 15 kPa.

When the pressure generated by the pore water is greater than the air pressure inside the hollow rubber balloon, the pore water pressure squeezes the hollow rubber balloon to deform, which weakens the pore water pressure and achieves the purpose of relieving the excess pore water pressure; when the pore water pressure is less than the hollow rubber balloon When the air pressure inside, the hollow rubber balloon returns to its original shape.

Preferably, the material of the spherical shell is low carbon stainless steel or hard plastic, which has high strength, rigidity and good corrosion resistance; the hollow rubber balloon has good elasticity and wear resistance and corrosion resistance.

Referring to FIG. 3 , this embodiment specifically describes the application of the buffer device of the present invention by taking a ballasted railway as an example.

The buffer device is arranged in the roadbed, the rigid device is used to carry and transmit the dynamic effective stress of the roadbed, and the flexible device is used to buffer the dynamic pore water pressure of the roadbed.

The number of the buffering devices is at least one piece, and multiple pieces of the buffering devices are evenly arranged on the surface layer of the subgrade bed of the roadbed and are filled with sand and gravel layers (that is, filled with sand and gravel around the buffering device).

The sandstone layer includes the first sandstone layer 4, the second sandstone layer 5 and the third sandstone layer 6; the sandstone filler with a good particle size of 1-20mm is evenly laid on the base bed 8. On the surface, a first sandstone layer 4 with a thickness of 5-6cm is formed, the buffer device is evenly arranged on the surface of the first sandstone layer 4, and then the sandstone filler with a particle size of 1-20mm with a good gradation is used to fill the buffer. Around the device, a second sandstone layer 5 with a thickness of 6-8cm is formed, and finally a sandstone filler with a particle size of 1-20mm with a good gradation is evenly laid on the second sandstone layer 5 and the buffer device to form a thickness of 1-20mm. The third sandstone layer 6 is 5-6cm. Finally, the ballast 3 , the sleepers 2 and the rails 1 are laid in sequence on the surface of the third sandstone layer 6 .

When the train comes, the subgrade soil skeleton is subjected to the dynamic load of the train, and the volume of the subgrade under load decreases rapidly. The dynamic pore water and a small amount of small soil particles attached to it enter the inner cavity of the rigid device (ie spherical shell) through the water passage hole, making the flexible pore water. The device (ie, the hollow rubber balloon) is deformed, which weakens the dynamic pore water pressure and achieves the purpose of alleviating the excess pore water pressure;

When the train leaves, the subgrade soil skeleton unloads the dynamic load of the train, and the volume of the subgrade unloading load position increases rapidly, forming a negative pore water pressure; under the action of the negative pore water pressure, the pore water in the inner cavity of the rigid device and a small amount of attached small soil The particles are sucked out to relieve the negative pore water pressure, and the flexible device recovers the deformation to prepare for the next dynamic load.

Applying the technical scheme of the present invention, the effect is:

The buffer device of the present invention ensures the stability of the roadbed through the rigid device, realizes the buffering of the dynamic pore water pressure of the roadbed through the flexible device, and the flexible device is arranged in the inner cavity of the rigid device to protect the flexible device and avoid the soil skeleton from causing the flexible device. Frontal impact, extending the life of the flexible device.

The buffering method of the invention can take into account the two processes of transient pore water pressure increase and dissipation, solve the problem of subgrade mud and mud from the root cause, and is not affected by the water content of the subgrade, and has high practicability.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. The transient pore water pressure buffering method for the railway subgrade is characterized by comprising a buffering device, wherein the buffering device comprises a rigid device and a flexible device, a cavity structure is arranged in the rigid device, at least one water passing hole communicated with an inner cavity is formed in the surface of the rigid device, and the flexible device is integrally arranged in the inner cavity of the rigid device;

the buffering method comprises the steps that the buffering device is arranged in a roadbed, the rigid device bears and transfers dynamic effective stress of the roadbed, and the flexible device buffers dynamic pore water pressure of the roadbed;

when a train comes, the roadbed soil framework is dynamically loaded by the train, the volume of the loaded position of the roadbed is rapidly reduced, and dynamic pore water enters the inner cavity of the rigid device through the water through holes, so that the flexible device is deformed, the dynamic pore water pressure is weakened, and the purpose of relieving the excess pore water pressure is achieved;

when the train leaves, the roadbed soil framework unloads the dynamic load of the train, the volume of the position of the roadbed unloading load is rapidly increased, and negative pore water pressure is formed; under the action of negative gap water pressure, pore water in the inner cavity of the rigid device is sucked out, the purpose of relieving the negative pore water pressure is achieved, and the flexible device recovers deformation and is ready for next dynamic load action.

2. The transient pore water pressure buffering method for railway subgrade as claimed in claim 1, wherein the number of said buffering devices is at least one, and a plurality of said buffering devices are uniformly arranged on the surface layer of the subgrade bed at intervals and are filled with a sandstone layer.

3. The utility model provides a railway roadbed transient state pore water pressure buffer, its characterized in that, including the rigidity device that is used for bearing and transmits roadbed developments effective stress and the flexible mounting who is used for buffering roadbed developments pore water pressure, the inside of rigidity device is equipped with cavity structures and is equipped with on the surface and crosses the water hole with at least one of inner chamber intercommunication, realizes through crossing the water hole that pore water flows in or flows the inner chamber, the flexible mounting whole set up in the inner chamber of rigidity device just the flexible mounting receives pore water pressure and takes place elastic deformation.

4. The transient pore water pressure buffering device of railway subgrade as claimed in claim 3, characterized in that said rigid device is a hollow spherical shell (7.1) and said flexible device is a hollow rubber balloon (7.3).

5. The transient pore water pressure buffering device for railway subgrade as claimed in claim 4, characterized in that the water through holes (7.2) are uniformly distributed on the surface of the spherical shell (7.1).

6. The transient pore water pressure buffering device for railway subgrade as claimed in claim 5, wherein the outer diameter of the spherical shell is 6-8cm, the thickness of the shell is 8-10mm, and the diameter of the water through hole is 4-5 mm.

7. The transient pore water pressure buffering device for railway subgrade as claimed in claim 4, wherein the air pressure inside the hollow rubber balloon (7.3) is 15-20 kPa.

8. The transient pore water pressure buffering device for railway subgrade as claimed in any one of claims 4-7, wherein the spherical shell is made of low carbon stainless steel or hard plastic.

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