A high-speed railway expansion rock cutting structure and design method and construction method

Abstract

The present invention relates to a high-speed railway swelling rock cutting structure and design method and construction method. The structure includes a permeable component, which is arranged on a swelling rock foundation, and the permeable component is used to infiltrate water into the swelling rock foundation; a water replenishment component, which is connected to the permeable component, and the water replenishment component is used to replenish water to the permeable component, so that the swelling rock foundation is in a saturated state; a support component, which is arranged on the swelling rock foundation at intervals along the line, and the support component is used to support the foundation plate. The present invention arranges the water replenishment component and the permeable component to form a set of water guide system, so that the swelling rock foundation is in a saturated state or the water content remains unchanged for a long time, and its swelling arch deformation occurs in advance, and the swelling arch or shrinkage sinking deformation is kept in a fixed state to effectively control the deformation, which fundamentally solves the technical problem of preventing and controlling the arch of the swelling rock foundation roadbed, has a simple structure, convenient and fast construction, controllable quality, low investment cost, and has a good prospect for promotion and application.

Description

Technical Field

[0001] The present invention relates to geotechnical engineering, and in particular to a cutting structure of expansive rock for high-speed railway, a design method and a construction method thereof. Background Art

[0002] With the rapid construction of high-speed railways in China, it is inevitable to encounter cutting sections of expansive rock. Expansive rock has the characteristics of swelling and softening when absorbing water and shrinking and cracking when losing water. After the excavation of cutting engineering, stress relaxation will occur in the expansive rock foundation and the water environment will change. Under the combined action, the environment where the cutting of expansive rock is located will be in a dynamic change process. Especially, the long-term changes of surface water and groundwater will have a great impact on the deformation of the expansive rock foundation, and this impact is usually difficult to control. High-speed railways have very strict requirements for deformation control. The post-construction deformation of subgrade settlement does not exceed 15 mm, and the upward arching deformation does not exceed 4 mm. It is relatively difficult to adjust and repair the subgrade settlement deformation, and it is extremely difficult to adjust and repair the upward arching deformation of the subgrade. In engineering practice, there have been many engineering problems of excessive upward arching deformation of cuttings of expansive rock for high-speed railways, which have seriously affected the operation of high-speed railways. At present, in the construction of high-speed railways, mainly measures such as increasing the depth of subgrade replacement, setting deep drainage blind ditches, and setting voided pile-slab structures are taken to deal with the expansive rock foundation. The main principle is to drain groundwater, control the influence depth of groundwater, and reserve space for expansion. However, these measures cannot accurately judge and effectively control the upward arching deformation amount of the expansive rock foundation, or the engineering construction and investment are very large. Summary of the Invention

[0003] The purpose of the present invention is to provide a cutting structure of expansive rock for high-speed railway, a design method and a construction method thereof, which have good anti-upward arching performance, simple structure, convenient and fast construction, good economy, and have good popularization and application prospects, aiming at the problems existing in the prior art.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A cutting structure of expansive rock for high-speed railway includes:

[0006] A water-permeable component, which is arranged on the expansive rock foundation and is used for seeping water into the expansive rock foundation;

[0007] A water supply component, which is connected to the water-permeable component and is used for supplying water to the water-permeable component to keep the expansive rock foundation in a saturated water state;

[0008] Support components, which are arranged on the expansive rock foundation at intervals along the line and are used for supporting the base plate.

[0009] Adopting a cutting structure for expansive rock in high-speed railways according to the present invention, a water conduction system is formed by setting the water replenishing component and the water permeable component, so as to fully introduce water into the expansive rock foundation, making the expansive rock foundation in a saturated water state or the water content remain unchanged for a long time. Under the action of water, the expansive upward arching deformation of the expansive rock foundation occurs in advance, and when the water content remains unchanged, the expansive upward arching or shrinkage and settlement deformation remains in a fixed state, thereby effectively controlling the adverse deformation of the high-speed railway subgrade built on the expansive rock foundation. Then, by setting the supporting component on the expansive rock foundation to support the high-speed railway base plate, the technical problem of preventing the upward arching of the subgrade on the expansive rock foundation is fundamentally solved, avoiding problems such as incomplete control of the upward arching deformation and excessive investment in engineering construction existing in the traditional anti-upward arching structure, and having a simple structure, convenient and fast construction, controllable quality, low investment cost, and good popularization and application prospects.

[0010] Preferably, the water permeable component includes a plurality of vertical water permeable bodies in a water permeable cushion layer. The vertical water permeable bodies are buried in the expansive rock foundation and are arranged in an array along the line. The water permeable cushion layer is arranged along the line on the top of the expansive rock foundation, and the top of the vertical water permeable body contacts the water permeable cushion layer.

[0011] Adopting this structure, the water permeable cushion layer serves as a planar water passing channel, which can effectively supplement the water volume of all the vertical water permeable bodies. The vertical water permeable bodies serve as vertical water permeable channels, enabling the expansive rock foundation to always be in a saturated water state.

[0012] Further preferably, the vertical water permeable body is made of a sand-gravel pile or a perforated high-strength PVC pipe, and the vertical water permeable body is in close contact with the hole wall of the expansive rock foundation.

[0013] The sand-gravel pile is made of medium-coarse sand or small-sized crushed stones with strong weather resistance, and the mud content is less than 5%.

[0014] Further preferably, the diameter of the vertical water permeable body is 49 mm - 60 mm.

[0015] Further preferably, the spacing of the vertical water permeable bodies is 3 m - 5 m.

[0016] Further preferably, the length of the vertical water permeable body is 5 m - 10 m.

[0017] Further preferably, the water permeable cushion layer is made of permeable soil or a composite drainage net.

[0018] Further preferably, the thickness of the permeable soil is set to be 0.2 m - 0.3 m.

[0019] Further preferably, a leveling layer is laid at the bottom of the composite drainage net.

[0020] Further preferably, the leveling layer is a medium-coarse sand layer with a thickness of 0.1m - 0.15m.

[0021] Further preferably, the water replenishing component includes a water storage tank and a water conduit. A number of the water storage tanks are arranged at intervals along the line, and each water storage tank is connected to the permeable cushion layer through the water conduit.

[0022] Further preferably, the spacing between the water storage tanks is 20m - 50m.

[0023] Further preferably, the elevation of the water level at the top of the water storage tank is at least 0.05m higher than the elevation of the bottom of the permeable cushion layer at the corresponding position, and the elevation of the water level at the top of the water storage tank is 0.1m - 0.15m lower than the elevation of the top of the base plate.

[0024] Adopting this structure can ensure that the permeable cushion layer and the vertical water permeable body on the expansive rock foundation always have a water source replenishment source and a flowing water pressure difference, and can ensure that the water in the permeable cushion layer does not overflow from the base plate.

[0025] Further preferably, the support component is a support cross beam. The support cross beam is arranged at intervals along the line on the expansive rock foundation, and the support cross beam is buried in the expansive rock foundation. The top of the support cross beam is at the same elevation as the top of the permeable cushion layer. The expansive rock foundation and the support cross beam are both used to support the base plate.

[0026] Further preferably, the spacing between the support cross beams is 5m - 8m.

[0027] Further preferably, the depth of the support cross beam buried in the expansive rock foundation is not less than 1m, which can transfer the upper load to the expansive rock foundation after immersion in water and has sufficient bearing capacity.

[0028] Further preferably, side ditches are respectively arranged on both sides along the line. The vertical water permeable bodies are arranged in a rectangular array. The support cross beam includes a number of end closed cross beams and a number of middle short cross beams. The end closed cross beams are arranged at both ends of the segmented cutting structure. The ends of the end closed cross beams are connected to the outer walls of the side ditches. At least one middle short cross beam is arranged in the segmented cutting structure. The middle short cross beam is arranged between two rows of the vertical water permeable bodies, and there is a gap between the end of the middle short cross beam and the side ditch.

[0029] Adopting this structure, the end closed cross beam and the side ditch are closed at the top of the segmented cutting structure, which can avoid the loss of water entering the segment. The gap at the end of the middle short cross beam can enable the water in the permeable cushion layer in the segment to be effectively transmitted to all the vertical water permeable bodies.

[0030] Further preferably, the length of the segmented cutting structure is 50m - 100m.

[0031] Further preferably, the end of the end-closed cross beam is connected to the outer wall of the side ditch through a water stop.

[0032] Further preferably, the clearance between the end of the middle short cross beam and the side ditch is not less than 0.5m.

[0033] Further preferably, the water guide pipe passes through the bottom of the side ditch, and both ends of the water guide pipe are respectively connected to the water storage pool and the permeable cushion layer.

[0034] Further preferably, the base plate is a reinforced concrete structure, and the base plate serves as the foundation of the upper railway track structure and transfers the upper load to the support components.

[0035] The present invention also provides a construction method for a high-speed railway expansive rock cutting structure for constructing the high-speed railway expansive rock cutting structure as described above. The method includes the following steps:

[0036] A. Excavate the cutting;

[0037] B. Locate the plane position of the vertical water-permeable body and drill holes, and construct the vertical water-permeable body in the drilled holes;

[0038] C. Locate the support cross beam, excavate the foundation pit groove of the support cross beam, pour the reinforced concrete of the support cross beam, and expose the connecting steel bars at the top of the middle short cross beam;

[0039] D. Lay the first layer of the permeable cushion layer on the foundation between the support cross beams;

[0040] E. Excavate the foundation pit groove of the side ditch, install the water guide pipe, extend the water guide pipe into the permeable cushion layer, pour the reinforced concrete of the side ditch, and the reinforced concrete of the side ditch is closely connected to the end-closed cross beam;

[0041] F. Construct the water storage pool, and connect and fix the water guide pipe to the bottom of the water storage pool;

[0042] G. Continuously store water in the water storage pool to keep the water levels of the vertical water-permeable body and the permeable cushion layer stable;

[0043] H. Conduct arching deformation observation on the expansive rock foundation under the railway until the arching deformation is stable;

[0044] I. Construct the remaining permeable cushion layer on the top of the first layer of the permeable cushion layer until the design elevation;

[0045] J. Construct the reinforced concrete of the base slab on the top of the permeable cushion layer, and fixedly connect the connecting steel bars exposed at the top of the middle short cross beam with the steel bars of the base slab.

[0046] Adopt the construction method of a high-speed railway expansive rock cutting structure described in the present invention. Segment the cutting structure through the end closed cross beam and the side ditch closed cutting structure, and jointly support the base slab through the end closed cross beam and the middle short cross beam, which can effectively supplement and prevent the loss of the water volume of all the vertical water permeable bodies within the segmented cutting structure. It has the characteristics of simple operation, clear steps, detailed key nodes, easy quality control, utilization and popularization, etc.

[0047] Preferably, in step A, the elevation of the foundation at the bottom of the railway subgrade structure is lower than the elevation of the railway subgrade surface after removing the thickness of the base slab, the thickness of the permeable cushion layer, and the estimated value of the upward arch of the expansive rock foundation due to saturated water.

[0048] Preferably, in step B, a geological drill is used for drilling.

[0049] Preferably, in step C, the length of the connecting steel bars exposed at the top of the middle short cross beam is 0.2m - 0.3m.

[0050] Preferably, in step D, when the permeable cushion layer uses permeable soil, the thickness of the first layer is 0.1m - 0.2m; when the permeable cushion layer uses a composite drainage net, a leveling layer of medium-coarse sand with a thickness of 0.1m - 0.15m is laid in the first layer.

[0051] Preferably, in step E, the water guide pipe extends into the permeable cushion layer by not less than 0.2m.

[0052] Preferably, in step E, a water stop is filled between the side ditch reinforced concrete and the end closed cross beam.

[0053] Preferably, after step F and before step G, the storage pool is filled with water, and the water flow connection between the storage pool, the water guide pipe, the permeable cushion layer, and the vertical water permeable bodies is checked. When the connection is good, the storage pool is continuously filled with water; if the connection is poor, inspection and repair are carried out.

[0054] Preferably, in step I, when the permeable cushion layer uses permeable soil, the upper permeable soil is constructed to the design elevation; when the permeable cushion layer uses a composite drainage net, medium-coarse sand is laid on the top of the composite drainage net to the design elevation.

[0055] Preferably, in step J, a layer of composite geomembrane is laid on the top of the permeable cushion layer, and the reinforced concrete of the base slab is constructed on the top of the composite geomembrane.

[0056] Preferably, after the step J, the railway track structure on the top of the base plate is constructed.

[0057] Preferably, the water level elevation of the water storage tank is monitored. When the water level elevation of the water storage tank drops to the middle elevation position of the permeable cushion layer, monitoring and early warning are carried out, and the water storage tank is replenished with water.

[0058] The present invention also provides a design method for a high-speed railway expansive rock cutting structure for designing the high-speed railway expansive rock cutting structure as described above. The method includes the following steps:

[0059] S1. Calculation of the bearing capacity of the saturated expansive rock foundation;

[0060] f a ′ = λξf a

[0061] In the formula, f′ a is the characteristic value of the bearing capacity of the saturated expansive rock foundation; f a is the characteristic value of the bearing capacity of the natural state expansive rock foundation, related to the buried depth and bottom width of the support cross beam; λ is the water saturation influence coefficient; ξ is the influence coefficient of the vertical water permeable body;

[0062] S2. Calculation of the average pressure value of the expansive rock foundation at the bottom of the support cross beam;

[0063]

[0064] F d = μF s = μP s L

[0065] F g = P g L

[0066] In the formula, p k is the average pressure value at the bottom of the support cross beam; F d is the train dynamic load acting on a single base plate; F s is the train static load acting on a single base plate; F g is the track load acting on a single base plate; μ is the train dynamic load influence coefficient; N is the number of support cross beams under a single base plate; P s 、P g are the train static load and track load acting on a single base plate per unit length along the line direction; L is the length of a single base plate along the line direction; G 1 is the self-weight of a single base plate; G 2 is the self-weight of a single support cross beam; A is the area of a single support cross beam;

[0067] S3. Bearing capacity check of the water-saturated expansive rock foundation;

[0068] γ 0 p k ≤f′ a

[0069] In the formula, γ 0 is the importance coefficient of the high-speed railway subgrade structure;

[0070] If the bearing capacity of the water-saturated expansive rock foundation meets the requirements, the design is completed;

[0071] If the bearing capacity of the water-saturated expansive rock foundation does not meet the requirements, adjust the setting depth or bottom width of the support cross beam described in step S1 and / or adjust the setting quantity N of the support cross beam described in step S2 until the bearing capacity of the water-saturated expansive rock foundation meets the design requirements.

[0072] The design method of a high-speed railway expansive rock cutting structure described in the present invention has the characteristics of simple principle, clear idea, easy operation, good effect on structural safety control, etc.

[0073] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0074] 1. For the high-speed railway expansive rock cutting structure described in the present invention, by setting the water replenishing component and the water permeable component to form a water guiding system, water is fully introduced into the expansive rock foundation, so that the expansive rock foundation is in a water-saturated state or the water content remains unchanged for a long time. Under the action of water, the expansive upward arching deformation of the expansive rock foundation occurs in advance, and when the water content remains unchanged, the expansive upward arching or shrinkage settlement deformation remains in a fixed state, thereby effectively controlling the adverse deformation of the high-speed railway subgrade built on the expansive rock foundation. Then, by setting the support component on the expansive rock foundation to support the high-speed railway base plate, the technical problem of preventing the upward arching of the expansive rock foundation subgrade is fundamentally solved, avoiding problems such as incomplete control of the upward arching deformation and excessive engineering construction investment existing in the traditional anti-upward arching structure, and having the advantages of simple structure, convenient and fast construction, controllable quality, low investment cost, and good popularization and application prospects;

[0075] 2. For the construction method of the high-speed railway expansive rock cutting structure described in the present invention, by segmenting with the end closing cross beam and the side ditch closing cutting structure, and jointly supporting the base plate by the end closing cross beam and the middle short cross beam, it can effectively make the water volume of all the vertical water permeable bodies in the segmented cutting structure be replenished without loss, and has the characteristics of simple operation, clear steps, detailed key nodes, easy quality control, and easy popularization;

[0076] 3. The design method of a high-speed railway expansive rock cutting structure according to the present invention has the characteristics of simple principle, clear idea, easy operation, and good effect on structural safety control. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 is a schematic plan view of the high-speed railway expansive rock cutting structure;

[0078] Figure 2 is Figure 1 the sectional view taken along line A-A in

[0079] Figure 3 is Figure 1 the sectional view taken along line B-B in

[0080] Reference numerals in the drawings: 1 - vertical water permeable body, 2 - water permeable cushion layer, 3 - base plate, 4 - water guide pipe, 5 - side ditch, 6 - water storage tank, 7 - end closed cross beam, 8 - middle short cross beam. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0081] The present invention will be described in detail below with reference to the accompanying drawings.

[0082] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0083] Embodiment 1

[0084] As Figures 1 to 3 shown, a high-speed railway expansive rock cutting structure according to the present invention includes a water permeable component, a water replenishing component and a supporting component.

[0085] The water permeable component is arranged on the expansive rock foundation. The water permeable component is used for seeping water into the expansive rock foundation. The water replenishing component is communicated with the water permeable component. The water replenishing component is used for replenishing water to the water permeable component so that the expansive rock foundation is in a saturated water state. The supporting component is arranged on the expansive rock foundation at intervals along the line. The supporting component is used for supporting the base plate 3.

[0086] In a specific embodiment, as Figure 2 shown, the water permeable component includes a plurality of vertical water permeable bodies 1 and a water permeable cushion layer 2. The vertical water permeable bodies 1 are buried in the expansive rock foundation and are arranged in an array along the line. As Figure 1 shown, the vertical water permeable bodies 1 are arranged in a rectangular array. As Figure 2 and Figure 3As shown, the permeable cushion layer 2 is arranged along the line on the top of the expansive rock foundation, and the top of the vertical water permeable body 1 contacts the permeable cushion layer 2; adopting this structure, the permeable cushion layer 2 serves as a planar water passage, which can effectively supplement the water volume of all the vertical water permeable bodies 1. The vertical water permeable body 1 serves as a vertical water permeable passage, enabling the expansive rock foundation to always be in a saturated water state.

[0087] Specifically, the vertical water permeable body 1 adopts a sand-gravel pile or a perforated high-strength PVC pipe with a diameter of 49 mm - 60 mm. The spacing of the vertical water permeable bodies 1 is 3 m - 5 m, and the length of the vertical water permeable body 1 is 5 m - 10 m. The vertical water permeable body 1 is in close contact with the hole wall of the expansive rock foundation. The sand-gravel pile adopts medium-coarse sand or small-sized crushed stones with strong weather resistance (the maximum particle size is less than 1 cm), and the mud content is less than 5%. The permeable cushion layer 2 adopts permeable soil (medium-coarse sand or crushed stones with strong weather resistance) or a composite drainage net. The thickness of the permeable soil is 0.2 m - 0.3 m. A leveling layer is laid at the bottom of the composite drainage net, and the leveling layer adopts a medium-coarse sand layer with a thickness of 0.1 m - 0.15 m.

[0088] In a specific embodiment, as Figure 1 and Figure 2 shown, the water supply component includes a water storage tank 6 and a water guide pipe 4. A number of the water storage tanks 6 are arranged at intervals along the line. The spacing of the water storage tanks 6 is 20 m - 50 m. Each water storage tank 6 is connected to the permeable cushion layer 2 through the water guide pipe 4. The water level elevation at the top of the water storage tank 6 is at least 0.05 m higher than the elevation at the bottom of the permeable cushion layer 2 at the corresponding position. The water level elevation at the top of the water storage tank 6 is 0.1 m - 0.15 m lower than the elevation at the top of the base plate 3; adopting this structure can ensure that the permeable cushion layer 2 and the vertical water permeable body 1 on the expansive rock foundation always have a water source replenishment source and a flowing water pressure difference, and ensure that the water in the permeable cushion layer 2 does not overflow from the base plate 3.

[0089] In a specific embodiment, as Figure 1 and Figure 3 shown, the support component is a support cross beam. The support cross beam is arranged at intervals along the line on the expansive rock foundation. The spacing of the support cross beam is 5 m - 8 m. The support cross beam is buried in the expansive rock foundation, and the burial depth is not less than 1 m, which can transfer the upper load to the expansive rock foundation after immersion and has sufficient bearing capacity. The top of the support cross beam is at the same elevation as the top of the permeable cushion layer 2. The expansive rock foundation and the support cross beam are both used to support the base plate 3.

[0090] Specifically, as Figures 1 to 3As shown in the figure, side ditches 5 are respectively provided on both sides of the line. The support cross beam includes a number of end-closed cross beams 7 and a number of middle short cross beams 8. The end-closed cross beams 7 are arranged at both ends of the segmented cutting structure. The length of the segmented cutting structure is 50m - 100m. The end of the end-closed cross beam 7 is connected to the outer wall of the side ditch 5 through a water stop member. At least one middle short cross beam 8 is arranged in the segmented cutting structure. The middle short cross beam 8 is arranged between two rows of the vertical water-permeable bodies 1. There is a gap between the end of the middle short cross beam 8 and the side ditch 5, and the gap is not less than 0.5m. The water guide pipe 4 passes through the bottom of the side ditch 5, and both ends of the water guide pipe 4 are respectively connected to the water storage pool 6 and the water-permeable cushion layer 2. With this structure, the end-closed cross beam 7 and the side ditch 5 are closed at the top of the segmented cutting structure, which can avoid the loss of water entering the segment. The gap at the end of the middle short cross beam 8 can effectively transfer the water in the water-permeable cushion layer 2 in the segment to all the vertical water-permeable bodies 1.

[0091] In a specific embodiment, as Figures 1 to 3 shown, the base plate 3 is a reinforced concrete structure. The base plate 3 serves as the foundation of the upper railway track structure and transfers the upper load to the support member.

[0092] A high-speed railway expansive rock cutting structure described in this embodiment forms a water guiding system by setting the water replenishing component and the water-permeable component, fully introducing water into the expansive rock foundation, so that the expansive rock foundation is in a saturated water state or the water content remains unchanged for a long time. Under the action of water, the expansive upward arching deformation of the expansive rock foundation occurs in advance, and when the water content remains unchanged, the expansive upward arching or shrinkage and settlement deformation remains in a fixed state, thereby effectively controlling the adverse deformation of the high-speed railway subgrade built on the expansive rock foundation. Then, by setting the support member on the expansive rock foundation to support the high-speed railway base plate 3, the technical problem of preventing the upward arching of the expansive rock foundation subgrade is fundamentally solved, avoiding problems such as incomplete control of the upward arching deformation and excessive engineering construction investment existing in the traditional anti-upward arching structure, and having a simple structure, convenient and fast construction, controllable quality, low investment cost, and good promotion and application prospects.

[0093] Embodiment 2

[0094] As Figures 1 to 3 shown, a construction method of a high-speed railway expansive rock cutting structure described in the present invention is used to construct the high-speed railway expansive rock cutting structure as described in Embodiment 1. The method includes the following steps:

[0095] A. Excavate the cutting, where the elevation of the foundation at the bottom of the railway subgrade structure is lower than the elevation of the railway subgrade surface - the thickness of the base slab 3 - the thickness of the permeable cushion layer 2 - the estimated value of the upward arching of the expansive rock foundation due to water saturation - 0.05 m;

[0096] B. Locate the plane position of the vertical water permeable body 1, drill holes using a geological drill, and construct the vertical water permeable body 1 in the drilled holes;

[0097] C. Position the support cross beam, excavate the foundation pit groove of the support cross beam, pour the reinforced concrete of the support cross beam, and 0.2 m - 0.3 m of the connecting steel bars are exposed at the top of the middle short cross beam 8;

[0098] D. Lay the first layer of the permeable cushion layer 2 on the foundation between the support cross beams. When the permeable cushion layer 2 uses permeable soil, the thickness of the first layer is 0.1 m - 0.2 m. When the permeable cushion layer 2 uses a composite drainage net, lay 0.1 m - 0.15 m thick medium - coarse sand as a leveling layer for the first layer;

[0099] E. Excavate the foundation pit groove of the side ditch 5, install the water guide pipe 4, the water guide pipe 4 extends into the permeable cushion layer 2 not less than 0.2 m, pour the reinforced concrete of the side ditch 5, and the reinforced concrete of the side ditch 5 is closely connected to the end - closed cross beam 7, and a water stop is stuffed between them;

[0100] F. Construct the water storage tank 6, and the water guide pipe 4 is connected and fixed to the bottom of the water storage tank 6;

[0101] G. Fill the water storage tank 6 with water, check the water flow connection between the water storage tank 6, the water guide pipe 4, the permeable cushion layer 2 and the vertical water permeable body 1. When the connection is good, the water storage tank 6 continuously stores water. When the connection is poor, check and repair;

[0102] H. After passing the inspection in step G, the water storage tank 6 continuously stores water to make the water levels of the vertical water permeable body 1 and the permeable cushion layer 2 stable;

[0103] I. Conduct upward arch deformation observation on the expansive rock foundation under the railway until the upward arch deformation is stable;

[0104] J. Construct the remaining permeable cushion layer 2 on the top of the first - layer permeable cushion layer 2 until the design elevation. When the permeable cushion layer 2 uses permeable soil, construct the upper permeable soil to the design elevation. When the permeable cushion layer 2 uses a composite drainage net, lay medium - coarse sand on the top of the composite drainage net to the design elevation;

[0105] K. Lay a layer of composite geomembrane on the top of the permeable cushion layer 2, and construct the reinforced concrete of the base slab 3 on the top of the composite geomembrane. The connecting steel bars exposed at the top of the middle short cross beam 8 are fixedly connected to the steel bars of the base slab 3;

[0106] L. Construct the railway track structure on the top of the base plate 3 during construction;

[0107] M. Continuously and automatically monitor the water level elevation of the water storage tank 6. When the water level elevation of the water storage tank 6 drops to the middle elevation position of the permeable cushion layer 2, conduct monitoring and early warning, and automatically replenish the water source for the water storage tank 6.

[0108] For the construction method of a high-speed railway expansive rock cutting structure described in this embodiment, the cutting structure is segmented by the end closed cross beam 7 and the side ditch 5, and the base plate 3 is supported jointly by the end closed cross beam 7 and the middle short cross beam 8, which can effectively replenish and prevent the loss of the water volume of all the vertical water permeable bodies 1 within the segmented cutting structure. It has the characteristics of simple operation, clear steps, detailed key nodes, easy quality control, and is suitable for popularization.

[0109] Embodiment 3

[0110] As Figures 1 to 3 shown, a design method of a high-speed railway expansive rock cutting structure described in the present invention is used to design the high-speed railway expansive rock cutting structure as described in Embodiment 1. This method includes the following steps:

[0111] S1. Calculate the bearing capacity of the saturated expansive rock foundation;

[0112] f′ a = λξf a

[0113] In the formula, f′ a is the characteristic value of the bearing capacity of the expansive rock foundation in the saturated state;

[0114] f a is the characteristic value of the bearing capacity of the expansive rock foundation in the natural state, and is corrected and calculated according to the "Code for Design of Subgrade and Foundation of Railway Bridges and Culverts" considering the buried depth of the support cross beam and the bottom width of the structure;

[0115] λ is the water saturation influence coefficient, that is, the ratio of the characteristic value of the bearing capacity of the expansive rock foundation in the saturated state to that in the natural state, which can be determined by the in-situ immersion load test. When there is no test condition, it can be analyzed according to the test statistical data. For weak expansive rock, it takes 0.7 - 0.9, for medium expansive rock, it takes 0.5 - 0.7, and for strong expansive rock, it takes 0.3 - 0.5;

[0116] ζ is the influence coefficient of the vertical water permeable body 1. According to the on-site test statistical results, for the water permeable body of perforated high-strength PVC pipe, it takes 0.8 - 0.9, and for the water permeable body of sand-gravel pile, it takes 0.9 - 1.0;

[0117] S2. Calculate the average pressure value of the expansive rock foundation at the bottom surface of the support cross beam;

[0118]

[0119] F d = μF s = μP s L

[0120] F g = P g L

[0121] where p k is the average pressure value at the bottom surface of the support cross beam;

[0122] F d is the dynamic train load acting on a single piece of the base plate 3;

[0123] F s is the static train load acting on a single piece of the base plate 3;

[0124] F g is the track load acting on a single piece of the base plate 3;

[0125] μ is the influence coefficient of the dynamic train load, which can be approximately taken as 2.0 according to the test results;

[0126] N is the number of the support cross beams under a single piece of the base plate 3. If the support cross beam supports two adjacent pieces of the base plate 3 at the same time, this support cross beam is calculated as 0.5 root;

[0127] P s 、P g are the static train load and the track load acting on a single piece of the base plate 3 per unit length along the line direction, and can be calculated according to the load distribution diagram of the subgrade surface and the uniform load table of the track and the train in the "Code for Design of High-Speed Railway";

[0128] L is the length of a single piece of the base plate 3 along the line direction;

[0129] G 1 is the self-weight of a single piece of the base plate 3;

[0130] G 2 is the self-weight of a single support cross beam;

[0131] A is the area of a single support cross beam, m 2 ;

[0132] S3. Check the bearing capacity of the foundation of the water-saturated expansive rock;

[0133] γ 0 p k ≤ f a

[0134] where γ 0It is the importance coefficient of the high-speed railway subgrade structure, taking 1.2 for ballasted railways and 1.3 for ballastless railways;

[0135] If the bearing capacity of the water-saturated expansive rock foundation meets the requirements, the design is completed;

[0136] If the bearing capacity of the water-saturated expansive rock foundation does not meet the requirements, the setting depth or bottom width of the support cross beam described in step S1 can be adjusted, and steps S1, S2, and S3 are repeated; or the setting quantity N of the support cross beam described in step S2 is adjusted, and steps S2 and S3 are repeated; or the setting depth or bottom width of the support cross beam described in step S1 and the setting quantity N of the support cross beam described in step S2 are adjusted simultaneously, and steps S1, S2, and S3 are repeated; until the bearing capacity of the water-saturated expansive rock foundation meets the design requirements.

[0137] The design method of a high-speed railway expansive rock cutting structure described in this embodiment has the characteristics of simple principle, clear idea, easy operation, and good effect on structural safety control.

[0138] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-speed railway expansion rock cutting structure, characterized in that: include: A water-permeable component is provided on the swelling rock foundation, and the water-permeable component is used to penetrate water into the swelling rock foundation; a water replenishing component connected to the water permeable component, the water replenishing component being used to replenish water to the water permeable component so that the swelling rock foundation is in a saturated state; Support components are arranged at intervals along the line on the expanded rock foundation, and the support components are used to support the base plate (3); The water-permeable component comprises a water-permeable cushion layer (2) and a plurality of vertical water-permeable bodies (1), wherein the vertical water-permeable bodies (1) are buried in the swelling rock foundation and arranged in an array along the line, and the water-permeable cushion layer (2) is arranged on the top of the swelling rock foundation along the line, and the top of the vertical water-permeable body (1) contacts the water-permeable cushion layer (2); The water replenishment component comprises a water reservoir (6) and a water conduit (4), a plurality of the water reservoirs (6) are arranged at intervals along the line, and each of the water reservoirs (6) is connected to the water-permeable cushion layer (2) via the water conduit (4); The supporting components are supporting beams, which are arranged at intervals along the route on the swelling rock foundation, and are buried in the swelling rock foundation. The top of the supporting beam is at the same elevation as the top of the permeable cushion layer (2), and the swelling rock foundation and the supporting beam are both used to support the foundation plate (3); Side ditches (5) are provided on both sides of the line respectively. The vertical permeable bodies (1) are arranged in a rectangular array. The supporting crossbeams include a plurality of end-closed crossbeams (7) and a plurality of middle short crossbeams (8). The end-closed crossbeams (7) are arranged at both ends of the segmented road cutting structure. The ends of the end-closed crossbeams (7) are connected to the outer walls of the side ditches (5). At least one middle short crossbeam (8) is provided in the road cutting structure segment. The middle short crossbeam (8) is provided between two rows of the vertical permeable bodies (1). There is a gap between the ends of the middle short crossbeam (8) and the side ditches (5).

2. The high-speed railway swelling rock cutting structure according to claim 1, characterized in that: The water level at the top of the water reservoir (6) is at least 0.05 m higher than the bottom elevation of the permeable cushion layer (2) at the corresponding position, and the water level at the top of the water reservoir (6) is 0.1 m-0.15 m lower than the top elevation of the foundation plate (3).

3. A construction method for a high-speed railway expansion rock cutting structure, characterized in that: Used for constructing the high-speed railway swelling rock cutting structure as claimed in claim 1 or 2, the method comprises the following steps: A. Excavation of road cutting; B. locating the plane position of the vertical water-permeable body (1) and drilling a hole, and constructing the vertical water-permeable body (1) in the drilled hole; C. Positioning the supporting crossbeam, excavating the foundation pit of the supporting crossbeam, pouring the reinforced concrete of the supporting crossbeam, and exposing the connecting steel bars at the top of the middle short crossbeam (8); D. Laying the first layer of the permeable cushion layer (2) on the foundation between the supporting beams; E. Excavating the foundation pit of the side ditch (5), installing the water conduit (4), extending the water conduit (4) into the permeable cushion layer (2), pouring the reinforced concrete of the side ditch (5), and the reinforced concrete of the side ditch (5) is tightly connected with the end closed cross beam (7); F. constructing a water storage tank (6), wherein the water conduit (4) is connected to and fixed to the bottom of the water storage tank (6); G. The water storage tank (6) continuously stores water so that the water levels of the vertical permeable body (1) and the permeable cushion layer (2) are stable; H. Observe the arch deformation of the swelling rock foundation under the railway until the arch deformation is stable; I. constructing the remaining permeable cushion layer (2) on top of the first layer of permeable cushion layer (2) until the designed elevation; J. The reinforced concrete of the foundation plate (3) is constructed on the top of the permeable cushion layer (2), and the connecting steel bars exposed on the top of the middle short cross beam (8) are fixedly connected to the steel bars of the foundation plate (3).

4. The construction method of the high-speed railway swelling rock cutting structure according to claim 3 is characterized in that: In the step J, a layer of composite geomembrane is laid on the top of the permeable cushion layer (2), and the reinforced concrete of the foundation plate (3) is constructed on the top of the composite geomembrane.

5. The construction method of the high-speed railway swelling rock cutting structure according to claim 3 is characterized in that: The water level of the water reservoir (6) is monitored, and when the water level of the water reservoir (6) drops to the middle elevation of the permeable cushion layer (2), monitoring and early warning are carried out, and water is replenished in the water reservoir (6).

6. A design method for a high-speed railway expansion rock cutting structure, characterized in that: For designing the high-speed railway swelling rock cutting structure as claimed in claim 1 or 2, the method comprises the following steps: S1. Calculation of bearing capacity of saturated swelling rock foundation; In the formula, f a ' is the characteristic value of the bearing capacity of the swelling rock foundation in a saturated state; f a is the characteristic value of the bearing capacity of the swelling rock foundation in the natural state, which is associated with the embedding depth and bottom width of the supporting beam; λ is the water saturation influence coefficient; ξ is the influence coefficient of the vertical permeable body (1); S2, calculation of the average pressure value of the swelling rock foundation on the bottom surface of the supporting beam; In the formula, p k is the average pressure value on the bottom surface of the supporting beam; F d The dynamic load of the train acting on the single base plate (3); F s The static load of the train acting on the single base plate (3); F g The track load acting on the single base plate (3); μ is the train dynamic load influence coefficient; N The number of supporting beams at the bottom of a single base plate (3); P s , P g The train static load and track load acting on a single base plate (3) per unit length along the line direction; L The length of a single base plate (3) along the line direction; G 1 is the deadweight of a single base plate (3); G 2 is the deadweight of a single supporting beam; A is the area of ​​a single supporting beam; S3. Verification of bearing capacity of saturated swelling rock foundation; In the formula, γ 0 is the importance coefficient of high-speed railway subgrade structure; If the bearing capacity of the saturated swelling rock foundation meets the requirements, the design is completed; If the bearing capacity of the saturated swelling rock foundation does not meet the requirements, adjust the depth or bottom width of the support beams in step S1 and / or adjust the number of support beams in step S2. N , until the bearing capacity of the saturated expansive rock foundation meets the design requirements.

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