Tunnel disease control structure and construction method of inclined pile grouting reinforcement

Abstract

A tunnel disease control structure and construction method using inclined pile grouting reinforcement, the control structure comprising a tunnel structure, an inclined pile group and a reinforcement area, the inclined pile group comprising a plurality of left inclined piles and right inclined piles, the left inclined piles and right inclined piles being respectively located in the soil layers on both sides of the tunnel structure, and being symmetrically or asymmetrically distributed, the left inclined piles and right inclined piles being cross-passed by each other at a certain distance at the bottom of the tunnel structure, the reinforcement area being located between the tunnel structure and the inclined pile group, and comprising a bottom reinforcement area and a side reinforcement area; thereby, the present invention can permanently improve the strength and bearing capacity of the soil outside the tunnel structure, solve problems such as soil disturbance and deformation around the tunnel structure, fundamentally avoid diseases such as uneven settlement and large deformation of the tunnel structure, improve the safety of the tunnel structure, and reduce subsequent operation and maintenance costs.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel structures, and in particular to an inclined pile grouting reinforcement type tunnel disease treatment structure and a construction method. Background Art

[0002] In the mining method structure or shield tunnel structure projects in operation, many tunnel structure diseases have appeared, such as uneven settlement, large deformation, leakage, cracking, etc. Especially in soft soil areas, most tunnel structures are in silty soft soil layers, which have unfavorable conditions such as large porosity, high water content, high compressibility, high sensitivity, low shear strength, small permeability, long consolidation and secondary consolidation settlement deformation time and flow deformation. In addition, due to the influence of many external operations and construction in the tunnel structure safety control protection area and the long-term vibration and sinking of trains, tunnel structure diseases are becoming more and more serious and complex.

[0003] In order to solve the problems of uneven settlement and large deformation of tunnel structures, the existing treatment methods are mostly grouting reinforcement on the outside of the tunnel structure or pasting flexible or rigid materials inside the tunnel structure. Although grouting reinforcement on the outside of the tunnel structure can improve the bearing capacity of the soil around the tunnel structure and has a positive effect on the treatment of tunnel structure diseases, the performance of the soil outside the reinforced area has not been fundamentally changed. In the subsequent operation, the tunnel structure will still disturb the soil in the non-reinforced area due to adjacent construction and train operation vibration, causing settlement and deformation of the soil in the non-reinforced area, which in turn causes uneven settlement and large deformation of the tunnel structure. Pasting flexible or rigid materials inside the tunnel structure can improve the strength of the tunnel structure, but when the strata around the tunnel are disturbed, the tunnel structure will separate from the pasted material due to secondary deformation, affecting the reinforcement effect.

[0004] To this end, in view of the above-mentioned defects, the designers of the present invention have devoted themselves to research and design, and combined the experience and achievements of many years in related industries to research and design a inclined pile grouting reinforcement type tunnel disease control structure and construction method to overcome the above-mentioned defects. Summary of the invention

[0005] The purpose of the present invention is to provide a tunnel disease control structure and construction method for inclined pile grouting reinforcement, which can permanently improve the strength and bearing capacity of the soil outside the tunnel structure, solve problems such as soil disturbance and deformation around the tunnel structure, fundamentally avoid diseases such as uneven settlement and large deformation of the tunnel structure, improve the safety of the tunnel structure, and reduce subsequent operation and maintenance costs.

[0006] To achieve the above object, the present invention discloses a tunnel disease treatment structure reinforced by inclined pile grouting, comprising a tunnel structure, an inclined pile group and a reinforcement area, characterized in that:

[0007] The inclined pile group includes a plurality of left-side inclined piles and right-side inclined piles, which are respectively located in the soil layers on both sides of the tunnel structure and are symmetrically or asymmetrically distributed. The left-side inclined piles and the right-side inclined piles are spaced a certain distance apart and cross each other at the bottom of the tunnel structure.

[0008] The reinforcement area is an area reinforced by grouting, located between the tunnel structure and the inclined pile group, and includes a bottom reinforcement area and a side reinforcement area. The bottom reinforcement area is located between the intersection area of ​​the left inclined pile and the right inclined pile and the bottom of the tunnel structure, and the side reinforcement area is located between the left inclined pile and the right inclined pile and the two sides of the tunnel structure.

[0009] Therefore, the inclined pile group composed of multiple inclined piles can effectively keep the reinforcement area between the tunnel structure and the inclined pile group stable and prevent deformation, forming an inclined pile grouting reinforcement tunnel disease control structure.

[0010] Wherein: a pre-buried grouting system is arranged inside the left inclined pile and the right inclined pile, and the pre-buried grouting system comprises a main grouting pipe extending from the pile top to the pile bottom and side grouting pipes spaced apart on both sides of the main grouting pipe and extending out from the pile wall, so that the pile bottom and the pile side are respectively reinforced by secondary grouting through the pre-buried grouting system, so that a pile bottom expansion area is formed through the bottom of the main grouting pipe, and a pile side expansion area is formed toward both sides of the pile wall through the side grouting pipe, so as to effectively increase the bearing capacity of the inclined pile and improve the safety performance and pressure bearing performance.

[0011] Among them: the left-side inclined piles and the right-side inclined piles are arranged in sequence along the longitudinal direction of the tunnel structure, cross each other just below the tunnel structure, and there is a certain distance between adjacent piles.

[0012] Where: The preliminary parameters of the length, diameter and inclination angle of the inclined pile are determined by calculation using formula (1):

[0013]

[0014] Q uk ——vertical bearing capacity of inclined piles;

[0015] Q sk ——Standard value of total limit pile side soil friction resistance in non-vertical grouting section;

[0016] Q gsk ——Standard value of total limit pile side soil friction resistance in vertical grouting section;

[0017] Q gpk ——Standard value of total ultimate bearing capacity of pile bottom and pile body soil layer;

[0018] d——diameter of inclined pile;

[0019] α——inclination angle of inclined pile;

[0020] l——length of inclined pile;

[0021] l j ——The vertical height of the inclined pile in the non-grouting section of the j-th soil layer;

[0022] l gi ——The vertical height of the grouting section of the inclined pile in the i-th soil layer;

[0023] l——the length of the inclined pile, l=l j / sinα+l gi / sinα;

[0024] q sik ,q sjk ,q pk ——respectively, the standard value of the initial limit pile side soil friction resistance of the i-th soil layer in the grouting section, the standard value of the initial limit pile side soil resistance of the i-th soil layer in the non-grouting section, and the standard value of the initial limit pile bottom and pile body soil bearing capacity;

[0025] β si , β p ——respectively represent the friction resistance of soil on the pile side and the bearing capacity enhancement coefficient of soil layer at the pile bottom and pile body.

[0026] Among them: when using ground drilling and grouting, first drill inclined holes from the ground along the left and right inclined piles to the bottom reinforcement area, insert the bottom grouting pipe, and at the same time grouting reinforcement to the bottom reinforcement area; after the grouting reinforcement of the bottom reinforcement area is completed, drill vertical holes from the ground to the side reinforcement area, and insert the side grouting pipe for grouting reinforcement. Both sides of the bottom reinforcement area and the side reinforcement area should be grouted evenly at the same time to avoid deformation of the tunnel structure due to uneven grouting pressure.

[0027] Also disclosed is a construction method for a tunnel disease control structure reinforced by inclined pile grouting, which is characterized by comprising the following steps:

[0028] Step 1: Obtain the tunnel structure coordinates, burial depth, diameter, and deformation parameters of the area to be reinforced;

[0029] Step 2: Determine the drilling points on the ground according to the location of the tunnel structure and the design parameters of the inclined piles;

[0030] Based on the confirmed inclined pile design parameters, the horizontal distance x between the tunnel structure and the ground drilling point is calculated by formula (2);

[0031] (2)

[0032] x——the horizontal distance between the tunnel structure and the ground drilling point;

[0033] h——the buried depth of tunnel structure;

[0034] r——radius of tunnel structure;

[0035] d 3 - Clearance between tunnel structure and inclined piles;

[0036] Step 3: After the inclined pile group is constructed, secondary grouting is performed at the pile bottom and pile side through the main grouting pipe and side grouting pipe of the pre-buried grouting system in the inclined pile group to form a pile bottom expansion area and a pile side expansion area, thereby achieving the expansion of the pile bottom and pile side and improving the grouting effect;

[0037] Step 4: Grouting is carried out into the reinforcement area from inside the tunnel structure or by drilling holes on the ground.

[0038] Among them: when ground drilling and grouting are adopted, grouting reinforcement is carried out by drilling inclined holes around the left inclined piles and the right inclined piles and inserting the bottom grouting pipes respectively. There is no obstruction above the side reinforcement area, and vertical holes are drilled directly from the ground and grouting reinforcement is carried out on the side reinforcement area through the side grouting pipes.

[0039] Among them: a casing with an inner diameter larger than the drill bit of the drilling rig is set at the mouth of the inclined hole. The casing stabilizes the wall of the inclined hole to prevent the hole from collapsing, assists the drill bit in guiding when entering the soil, controls the inclination angle of the inclined hole, and the length of the casing extends to the bottom of the hole, and is gradually pulled out as the concrete is subsequently penetrated;

[0040] Long guide cylinders are arranged at a certain interval on the drill rod, the drill rod is located in the center of the guide cylinder, and both ends of the guide cylinder are arranged to be tapered. On the one hand, the drill rod is controlled to always be located in the center of the inclined hole to avoid hole position deviation; on the other hand, the tapered mouth helps the drill rod to move smoothly in the inclined hole.

[0041] Wherein: a guide bracket is arranged on the catheter to ensure that the catheter is located in the center of the left oblique hole and the right oblique hole.

[0042] From the above content, it can be seen that the inclined pile grouting reinforcement tunnel disease control structure and construction method of the present invention have the following effects:

[0043] 1. By setting up a cross-arranged inclined pile group outside the tunnel structure and grouting the soil between the inclined pile group and the tunnel structure. The inclined pile group itself has high strength, and the surrounding soil has a large friction and high bearing capacity to it, and can be regarded as a fixed, non-deformed, and non-settled supporting structure. Under the protection of the inclined pile group, the reinforced soil between the tunnel structure and the inclined pile group maintains the stability and bearing capacity of the soil in the reinforced area around the tunnel structure for a long time, reduces uneven settlement, large deformation and other diseases of the tunnel structure, and improves the safety and service life of the tunnel structure.

[0044] 2. It can permanently change the boundary conditions of the tunnel structure and only requires a one-time investment in the early stage. Compared with the existing reinforcement scheme that requires multiple and uninterrupted grouting reinforcements, it can greatly reduce project costs, reduce human and material investment, and has higher economic and social benefits.

[0045] The details of the present invention can be obtained from the following description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The schematic diagram of the structure of the inclined pile grouting reinforcement tunnel disease treatment structure of the present invention is shown.

[0047] Figure 2 Shows Figure 1 Schematic diagram of the A-A section.

[0048] Figure 3 Shows Figure 1 Schematic diagram of the B-B section.

[0049] Figure 4 The force diagram of the inclined pile of the present invention is shown.

[0050] Figure 5A and Figure 5B A schematic diagram showing the geometric relationship of the inclined pile grouting reinforcement type tunnel disease treatment structure of the present invention is shown.

[0051] Figure 6 The schematic diagram of horizontal convergence deformation of inclined pile grouting reinforcement structure and traditional grouting reinforcement structure is shown.

[0052] Figure 7 The vertical convergence deformation schematic diagram of the inclined pile grouting reinforcement structure and the traditional grouting reinforcement structure is shown.

[0053] Fig. 8A The schematic diagram of the numerical simulation of the traditional grouting reinforcement structure for the side-penetration condition of a newly built tunnel is shown.

[0054] Figure 8B The schematic diagram of numerical simulation of inclined pile grouting reinforcement structure for side penetration of a new tunnel is shown.

[0055] Fig. 9 The schematic diagram of horizontal deformation of the inclined pile grouting reinforcement structure and the traditional grouting reinforcement structure under the side-penetration condition of a newly built tunnel is shown.

[0056] Fig. 10A The schematic diagram of the numerical simulation of the traditional grouting reinforcement structure for the underpass condition of a newly built tunnel is shown.

[0057] Fig. 10B The schematic diagram of numerical simulation of inclined pile grouting reinforcement structure under the new tunnel is shown.

[0058] Fig.11 The vertical deformation diagram of the inclined pile grouting reinforcement structure and the traditional grouting reinforcement structure under the new tunnel underpass condition is shown.

[0059] Fig.12A schematic diagram of the inclined pile drilling scheme provided by the present invention is shown.

[0060] Fig.13 A schematic diagram of the catheter structure provided by the present invention is shown.

[0061] Reference numerals:

[0062] 100: tunnel structure; 101: left inclined hole; 102: left inclined pile; 103: right inclined hole; 104: right inclined pile; 105 ground; 106: main grouting pipe; 107: side grouting pipe; 108: pile bottom expansion area; 109: pile side expansion area; 201: bottom grouting pipe; 202: side grouting pipe; 203: bottom reinforcement area; 204: side reinforcement area; 301: drilling rig; 302: drill rod; 303: drill bit; 304: guide tube; 305: casing; 306: guide tube; 307: guide tube bracket. DETAILED DESCRIPTION

[0063] See also Figures 1 to 3 , showing a preferred embodiment of the inclined pile grouting reinforcement tunnel disease control structure of the present invention.

[0064] like Figure 1 , Figure 2 and Figure 3 As shown, the inclined pile grouting reinforcement type tunnel disease control structure includes a tunnel structure 100, an inclined pile group and a reinforcement area. In this embodiment, the control structure of the present invention has no special requirements on the cross-sectional type and size of the tunnel structure 100, and can be well applied to shield tunnel structures and mining method tunnel structures. There are no special requirements on the stratum conditions in which the tunnel structure 100 is located, and it can also be applied to clay strata, sandy strata, gravel strata, etc., so it has strong applicability and can be applied to various tunnel structures.

[0065] The inclined pile group includes a plurality of left inclined piles 102 and right inclined piles 104. Figure 1 As shown, the left inclined piles 102 and the right inclined piles 104 are respectively located in the soil layers on both sides of the tunnel structure 100 and are symmetrically or asymmetrically distributed. The left inclined piles 102 and the right inclined piles 104 cross and pass each other at a certain distance at the bottom of the tunnel structure 100.

[0066] Among them, the reinforced area is an area reinforced by grouting, which is mainly located between the tunnel structure 100 and the inclined pile group. It may include a bottom reinforcement area 203 and a side reinforcement area 204. The bottom reinforcement area 203 is located between the intersection area of ​​the left inclined pile 102 and the right inclined pile 104 and the bottom of the tunnel structure 100, and the side reinforcement area 204 is located between the left inclined pile 102 and the right inclined pile 104 and the two sides of the tunnel structure.

[0067] Therefore, since the inclined piles themselves have high strength and are not prone to deformation, and the contact area between the inclined piles and the surrounding soil is large, the soil has a greater supporting effect on them. The inclined pile group composed of multiple inclined piles has high anti-deformation ability, anti-disturbance ability, bearing capacity, etc., which can effectively keep the tunnel structure 100 and the reinforced area between the inclined pile group stable and non-deformed, thereby effectively protecting the tunnel structure 100 from external disturbances. The tunnel structure 100, the inclined pile group and the reinforced area together constitute the inclined pile grouting reinforcement type tunnel disease control structure.

[0068] Preferably, the inclined pile group can select cast-in-place piles, precast piles and other types according to the formation conditions and the surrounding environment. For example, cast-in-place piles have no requirements for formation conditions and are not limited in length and diameter, but the cost is slightly higher and the construction period is longer; precast piles require that the formation is free of boulders, obstacles, etc. and the pile length is limited, but the cost is low and the construction efficiency is high. The left inclined pile 102 and the right inclined pile 104 can be provided with a pre-buried grouting system inside, and the pre-buried grouting system includes a main grouting pipe 106 extending from the pile top to the pile bottom and side grouting pipes 107 spaced apart on both sides of the main grouting pipe 106 and extending out from the pile wall, so that the pile bottom and pile side can be reinforced by secondary grouting respectively through the pre-buried grouting system, so that a pile bottom expansion area 108 can be formed through the bottom of the main grouting pipe 106, and a pile side expansion area 109 can be formed on both sides of the pile wall through the side grouting pipe 107, so as to effectively increase the bearing capacity of the inclined pile and improve the safety performance and pressure bearing performance.

[0069] Preferably, a certain distance should be reserved between the left inclined pile 102 and the right inclined pile 104 and the tunnel structure 100 to meet the safety construction requirements. The minimum distance should take into account the drilling deviation of the inclined hole, tunnel deformation, etc.

[0070] Preferably, if Figure 2 As shown, the left inclined pile 102 and the right inclined pile 104 are arranged in sequence along the longitudinal direction of the tunnel structure 100, cross each other just below the tunnel structure 100, and there is a certain distance between adjacent piles to ensure that the completed inclined piles are not damaged during the piling or drilling process.

[0071] Preferably, the inclined pile group is located on both sides of the tunnel structure 100. The load on the inclined piles after the boundary conditions of the tunnel structure 100 change needs to be balanced by the bearing capacity of the inclined piles. The bearing capacity of the inclined piles on the tunnel structure 100 mainly includes the friction resistance of the soil on the pile side, the bearing capacity of the soil at the pile bottom and the bearing capacity of the soil in the pile body, and the influence of the grouting reinforcement of the inclined pile pre-buried grouting system on the soil needs to be considered. The bearing capacity design requirements of the inclined pile group are proposed based on the current conditions of the tunnel structure 100. Under the premise of meeting the given design requirements, the preliminary parameters such as the length, diameter, and inclination angle of the inclined pile are determined by trial calculation through formula (1).

[0072] Specifically, under the premise that the required bearing capacity of the inclined pile is known, we first assume that the diameter, inclination, length, and grouting reinforcement points of the inclined pile are 80 cm in diameter, 25 m in length, and 55° inclination. The influence range of the pile bottom and pile side reinforcement is determined according to the influence range of the slurry (which can be tested or experienced). Then, we substitute it into formula (1) to calculate whether the bearing capacity requirements are met. If not, we can increase the diameter, length and other parameters. Similar to structural reinforcement, given the structural bearing capacity, the diameter and number of steel bars are selected. Then, based on the preliminary inclined pile design parameters, the space conditions around the tunnel structure, and the pile foundation design specifications, the inclined pile group layout is determined, such as the inclined pile spacing t, the net distance d between the tunnel structure and the inclined piles. 3 Finally, a three-dimensional numerical model including the inclined pile group and the tunnel structure 100 is established to verify whether the internal force, deformation and other parameters of the tunnel structure 100 under the design condition meet the reinforcement requirements.

[0073] If the requirement is met, the construction will be carried out with the parameters, otherwise the parameters will be adjusted by trial calculation until the requirement is met.

[0074] like Figure 4 As shown in Figure 1, the vertical bearing capacity of a single inclined pile can be calculated according to formula (1):

[0075]

[0076] Q uk ——vertical bearing capacity of inclined piles;

[0077] Q sk ——Standard value of total limit pile side soil friction resistance in non-vertical grouting section;

[0078] Q gsk ——Standard value of total limit pile side soil friction resistance in vertical grouting section;

[0079] Q gpk ——Standard value of total ultimate bearing capacity of pile bottom and pile body soil layer;

[0080] d——diameter of inclined pile;

[0081] α——inclination angle of inclined pile;

[0082] l——length of inclined pile;

[0083] l j ——The vertical height of the inclined pile in the non-grouting section of the j-th soil layer;

[0084] l gi ——The vertical height of the grouting section of the inclined pile in the i-th soil layer;

[0085] l——the length of the inclined pile, l=l j / sinα+l gi / sinα;

[0086] q sik ,q sjk ,q pk ——respectively, the standard value of the initial limit pile side soil friction resistance of the i-th soil layer in the grouting section, the standard value of the initial limit pile side soil resistance of the i-th soil layer in the non-grouting section, and the standard value of the initial limit pile bottom and pile body soil bearing capacity; determined according to JGJ94 standard;

[0087] β si , β p ——respectively represent the friction resistance of soil on the pile side, and the bearing capacity enhancement coefficient of soil layer at the pile bottom and pile body. When there is no local experience, it can be determined according to JGJ94 specification.

[0088] Preferably, after the construction of the inclined pile group is completed, grouting construction of the reinforcement area is carried out, and grouting from the inside of the tunnel structure 100 to the reinforcement area and drilling grouting on the ground 105 can be adopted. When grouting from the inside of the tunnel structure 100 to the reinforcement area, grouting can be performed according to the design requirements through the pre-buried grouting holes of the tunnel structure 100, but due to the restrictions on the arrangement position and angle of the grouting holes, there is a situation of insufficient grouting. When drilling grouting on the ground 105, firstly, inclined holes are drilled from the ground along the left inclined piles 102 and the right inclined piles 104 to the bottom reinforcement area 203, and the bottom grouting pipe 201 is inserted, and grouting reinforcement is performed to the bottom reinforcement area 203 at the same time; after the grouting reinforcement of the bottom reinforcement area 203 is completed, vertical holes are drilled from the ground to the side reinforcement area 204, and the side grouting pipe 202 is inserted for grouting reinforcement. The bottom reinforcement area 203 and both sides of the side reinforcement area 204 should be grouted evenly at the same time to avoid deformation of the tunnel structure 100 due to uneven grouting pressure.

[0089] like Figure 5A and Figure 5B As shown, the geometric relationship of the inclined pile grouting reinforcement tunnel disease treatment structure of the present invention is shown, wherein α 1 , l 1 and d 1 are the inclination angle, pile length and pile diameter of the left inclined pile respectively; α 2 , l 2 and d 2 They are the inclination angle, pile length and pile diameter of the right side inclined pile, which must meet the following requirements:

[0090] Min{α 1 , α 1}>50°, the inclination angle of the inclined pile should not be too small to ensure that the length of the inclined pile can be reduced under the same pile body length, which is convenient for construction.

[0091] When the ground conditions on both sides of the tunnel structure are slightly different, or when the tunnel is overloaded or underpassed, the left and right inclined piles can be designed symmetrically. The inclination angles and lengths of the inclined piles should be the same to ensure that the tunnel structure does not bear eccentric loads; that is, α 1 =α2 , l 1 =l 2 .

[0092] When the ground conditions on both sides of the tunnel structure are quite different, or when the tunnel structure is subjected to eccentric loading, side crossing of the tunnel, and other working conditions, resulting in uneven loads on both sides of the tunnel structure, an asymmetric design of left and right inclined piles can be adopted, and the inclined piles can have different inclination angles, lengths, diameters, etc.; if the new tunnel passes through the existing tunnel structure from the right side, an α 2 >α 1 d 2 >d 1 , l 2 <l 1 Design, using a larger inclination angle can reduce the impact of right-side unloading on the right-side inclined pile, a larger diameter can improve the bearing capacity of the right-side inclined pile, and a shorter pile length can ensure a lower cost for the same pile depth; similarly, when the new tunnel passes through the existing tunnel structure from the left, α 1 >α 2 d 1 >d 2 , l 1 <l 2 design.

[0093] Among them, n 1 and n 2 are the number of inclined piles on the left and right respectively. The amount of concrete used for the inclined pile group can be calculated as follows: V=π(d 1 / 2) 2 l 1 n 1 +π(d 2 / 2) 2 l 2 n 2 .

[0094] Preferably, a three-dimensional model of the inclined pile grouting reinforcement structure and the traditional grouting reinforcement structure is established based on the Midas GTS NX software using the stratum-structure model to simulate the deformation of the shield tunnel structure when the ground is overloaded. The model size is 54m×48m×3.6m. The shield tunnel structure uses C50 concrete with an outer diameter of 6.0m, a thickness of 0.3m, a ring width of 1.2m, and a burial depth of 12m. The modified Mohr-Coulomb model is selected as the soil model. The stratum is a homogeneous silt sand layer with a bulk density of 20.3kN / m 3 , elastic modulus 24142.9kN / m 2 , Poisson's ratio 0.3, friction angle 36°, cohesion 30kPa. The triaxial test secant stiffness of the reinforcement area is 6500kN / m2, the unloading elastic modulus is 65MPa, and the expansion angle is 10°.

[0095] The four inclined piles of the inclined pile grouting reinforcement structure are inserted from the ground into the soil layer at an inclination angle of 36.5°. The inclined pile group uses C35 plain concrete, with a diameter of 1.0m and a length of 33m. The minimum distance from the shield tunnel structure 100 is 0.3m. Grouting reinforcement is performed around the inclined pile group and the shield tunnel structure 100. The traditional grouting reinforcement structure only performs grouting reinforcement within 1.5m outside the shield tunnel structure.

[0096] Preferably, after the three-dimensional model is established, ground stress balance is performed and deformation is eliminated, and then a uniformly distributed load of 50 kPa is applied above the tunnel structure to simulate the ground overload condition.

[0097] Preferably, Figure 6 and Figure 7 The horizontal convergence deformation and vertical convergence deformation of the inclined pile grouting reinforcement and the traditional grouting reinforcement structure after ground overload are shown. The maximum horizontal convergence deformation of the traditional grouting reinforcement structure and the inclined pile grouting reinforcement structure are 4.85mm and 3.46mm respectively; compared with the traditional grouting reinforcement structure, the horizontal convergence deformation of the inclined pile grouting reinforcement structure is reduced by 29%. Affected by the overload, both the traditional grouting reinforcement structure and the inclined pile grouting reinforcement structure have experienced settlement in the vertical direction, but the vertical convergence deformation of the shield tunnel structure under the two reinforcement methods is very different, with the maximum vertical convergence deformation of 6.76mm and 3.73mm respectively. Compared with the traditional grouting reinforcement structure, the vertical convergence deformation of the shield tunnel structure of the inclined pile grouting reinforcement structure is reduced by 45%. The ovality of the traditional grouting reinforcement structure and the inclined pile grouting reinforcement structure is 2.15‰ and 1.33‰ respectively. Compared with the traditional grouting reinforcement structure, the ovality of the inclined pile grouting reinforcement structure is reduced by 38.1%. Under overload conditions, the convergence deformation of the tunnel structure with inclined pile grouting reinforcement structure is much smaller than that of the traditional grouting reinforcement structure. It can effectively change the boundary conditions of the shield tunnel structure, improve the bearing capacity and deformation resistance of the tunnel structure, and achieve better disease control effects.

[0098] Preferably, the numerical simulation results of working conditions such as a new tunnel passing under or sideways through an existing tunnel show that the tunnel structure convergence deformation of the inclined pile grouting reinforcement structure is smaller than that of the traditional grouting reinforcement structure, and the disease control effect is better.

[0099] Among them, in the tunnel side crossing condition:

[0100] The structural design parameters and stratum parameters of the inclined pile grouting reinforcement and the traditional grouting reinforcement structure are consistent with the ground overload condition. After the three-dimensional model is established, the ground stress balance is carried out and the deformation is eliminated. Then the shield tunnel is excavated on one side of the tunnel structure. The horizontal clearance between the two tunnels is 7m. The model diagram is as follows Fig. 8A and Figure 8B shown.

[0101] Preferably, Fig. 9The horizontal displacement of the tunnel structure under the side-through condition of the inclined pile grouting reinforcement and the traditional grouting reinforcement structure is shown. The maximum horizontal displacements of the traditional grouting reinforcement structure and the inclined pile grouting reinforcement structure are 2.00mm and 1.52mm respectively; compared with the traditional grouting reinforcement structure, the horizontal displacement of the inclined pile grouting reinforcement structure is reduced by 24.2%. The maximum horizontal convergence deformation of the traditional grouting reinforcement structure and the inclined pile grouting reinforcement structure are -0.62mm and -0.32mm respectively; compared with the traditional grouting reinforcement structure, the horizontal convergence deformation of the inclined pile grouting reinforcement structure is reduced by 48.1%. Compared with the traditional grouting reinforcement structure, the ovality of the inclined pile grouting reinforcement structure is reduced by 10.6%.

[0102] In tunnel underpass conditions:

[0103] The structural design parameters and formation parameters of the inclined pile grouting reinforcement and the traditional grouting reinforcement structure are consistent with the ground overload condition. After the three-dimensional model is established, the ground stress balance is carried out and the deformation is eliminated. Then the shield tunnel is excavated under the tunnel structure. The vertical clearance between the two tunnels is 4m. The model diagram is as follows Fig. 10A and Fig. 10B shown.

[0104] Preferably, Fig.11 The vertical displacement of the tunnel structure under the underpass condition of the inclined pile grouting reinforcement and the traditional grouting reinforcement structure is shown. The maximum vertical displacements of the traditional grouting reinforcement structure and the inclined pile grouting reinforcement structure are -3.10mm and -1.77mm respectively; compared with the traditional grouting reinforcement structure, the vertical displacement of the inclined pile grouting reinforcement structure is reduced by 42.9%. The maximum vertical convergence deformation of the traditional grouting reinforcement structure and the inclined pile grouting reinforcement structure are -0.045mm and -0.040mm respectively; compared with the traditional grouting reinforcement structure, the vertical convergence deformation of the inclined pile grouting reinforcement structure is reduced by 11.8%. Compared with the traditional grouting reinforcement structure, the ovality of the inclined pile grouting reinforcement structure is reduced by 12.5%.

[0105] like Fig.12 and Fig.13 As shown, the present invention also provides a construction method for a tunnel disease control structure reinforced by inclined pile grouting, and the construction method comprises the following steps:

[0106] Step 1: Obtain the coordinates, burial depth, diameter, deformation and other design and monitoring parameters of the tunnel structure 100 in the area to be reinforced. The coordinates, burial depth and diameter can be determined by the previous tunnel structure design parameters. Considering that the tunnel structure 100 will produce structural settlement and convergence deformation during construction and operation, the actual position of the tunnel structure 100 cannot ignore the impact of deformation. Since the inclined pile drilling needs to be close to the tunnel structure 100, accurate tunnel structure 100 position coordinates are the key to ensuring the reinforcement effect. At the same time, it can also avoid damage to the tunnel structure during drilling due to incorrect positional relationship between the tunnel structure 100 and the inclined pile group.

[0107] Step 2: Determine the drilling points on the ground 105 according to the position of the tunnel structure 100 and the design parameters of the inclined piles.

[0108] Preferably, the bearing capacity design requirements of the inclined pile group can be proposed according to the current conditions of the tunnel structure 100. Under the premise of meeting the given design requirements, the length, diameter, inclination angle and other preliminary parameters of the inclined pile are determined by trial calculation through formula (1), and then the arrangement of the inclined pile group is determined based on the preliminary inclined pile design parameters, the space conditions around the tunnel structure, and the requirements of the pile foundation design specification, such as the inclined pile spacing t, the clear distance d between the tunnel structure and the inclined pile. 3 Etc., and finally, a three-dimensional numerical model including the inclined pile group and the tunnel structure 100 is established to verify the reinforcement effect of the proposed inclined pile design parameters on the tunnel structure 100.

[0109] Then, based on the confirmed inclined pile design parameters, the horizontal distance x between the tunnel structure 100 and the drilling point on the ground 105 is calculated by equation (2).

[0110] (2)

[0111] x——the horizontal distance between the tunnel structure and the ground drilling point;

[0112] h——the buried depth of tunnel structure;

[0113] r——radius of tunnel structure;

[0114] d 3 ——The clear distance between the tunnel structure and the inclined piles.

[0115] Based on the coordinates of the axis of the tunnel structure 100 corresponding to the ground, the drilling points of the ground 105 can be obtained according to the horizontal distance x between the tunnel structure 100 and the drilling points of the ground 105, and the spacing t of the inclined piles. If the design parameters of the left inclined pile and the right inclined pile are different, then x is different, and the drilling points of the ground 105 need to be calculated separately, and the ground 105 is processed, and the ground 105 is reinforced if necessary. When prefabricated piles are used, the inclined piles can be directly pressed or driven into the two sides of the tunnel structure 100 at intervals according to the design angle by the pile driver; when bored piles are used, the drilling machine 301 is adjusted to the set angle, and holes are drilled from both sides of the tunnel structure 100 in turn. After the drilling is completed, concrete should be injected into the left inclined hole 101 and the right inclined hole 102 through the inclined guide tube 306 to form the left inclined pile 102 and the right inclined pile 104. Before the concrete is injected, the hole needs to be cleaned to remove the sediment at the bottom of the hole to ensure the bearing capacity of the pile foundation.

[0116] Step 3: After the inclined pile group is constructed, secondary grouting is performed at the pile bottom and pile side through the main grouting pipe 106 and the side grouting pipe 107 of the pre-buried grouting system in the inclined pile group to form a pile bottom expansion area 108 and a pile side expansion area 109, thereby expanding the pile bottom and pile side and improving the grouting effect;

[0117] Step 4: Grouting the reinforcement area from inside the tunnel structure or grouting through ground drilling. When grouting the reinforcement area from inside the tunnel structure is used, grouting can be performed according to the design requirements through the pre-buried grouting holes of the tunnel structure 100. When ground drilling grouting is used, since the bottom reinforcement area 203 is located in the triangular area formed by the tunnel structure 100, the left inclined piles 102 and the right inclined piles 104, grouting reinforcement can be performed by drilling inclined holes around the left inclined piles 102 and the right inclined piles 104 and inserting the bottom grouting pipes 201 respectively. There is no obstruction above the side reinforcement area 204, and vertical holes can be drilled directly from the ground 105 and grouting reinforcement can be performed on the side reinforcement area 204 through the side grouting pipes 202.

[0118] Preferably, the parameters such as the inclination angle and drilling depth of the drilling rig 301 used must meet the design requirements, and must be equipped with a drill rod 302 with greater rigidity to ensure that the inclination angle of the drill rod 302 is controllable during the inclined hole drilling process. It is advisable to use a positive circulation drilling rig, reverse circulation drilling rig, rotary drilling rig, etc. with a drill rod 302, and it is not advisable to choose a drilling rig that is raised and lowered by a wire rope, such as an impact drill and an impact grab drill.

[0119] Preferably, if Fig.12 As shown, the inclined hole is provided with a casing 305 whose inner diameter is slightly larger than the drill bit 303 of the drilling rig 301. The main functions of the casing 305 include stabilizing the wall of the inclined hole to prevent the hole from collapsing, assisting the drill bit 303 in guiding when entering the soil, controlling the inclination angle of the inclined hole, and protecting the original operating ground. For loose and unstable formations such as silt sand, quicksand, sand and gravel, in order to ensure that the wall of the full-depth inclined hole does not collapse, the length of the casing 305 can be extended to the bottom of the hole, and gradually pulled out with the subsequent penetration of concrete. At the same time, a long strip of guide cylinder 304 can be set at a certain distance on the drill rod 302, and the drill rod 302 is located at the center of the guide cylinder 304. The two ends of the guide cylinder 304 are set to be constricted. On the one hand, the drill rod 302 is always controlled to be located at the center of the inclined hole to avoid hole position deviation; on the other hand, the constriction helps the drill rod 302 to move smoothly in the inclined hole.

[0120] like Fig.13 As shown, the conduit structure used in the present invention is shown. When a cast-in-place pile is used, in order to ensure smooth penetration of concrete, a guide bracket 307 similar to the guide cylinder 304 needs to be provided on the conduit 306 to ensure that the conduit 306 is located in the center of the left inclined hole 101 and the right inclined hole 103. Concrete can be poured directly into the ground, or after being poured to a certain depth, the top is filled with soil.

[0121] Preferably, if reinforced concrete cast-in-place piles are used, arc-shaped steel bar brackets may be provided inside the steel cage to support the conduit 306 , and the conduit 306 may not be provided with a guide bracket 307 .

[0122] It should be noted that the above-mentioned specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention specification and its drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of the present invention is defined by the claims and their equivalents. The present invention specification contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally", which means that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to file a divisional application based on each inventive concept.

Claims

1. A tunnel disease control structure reinforced by inclined pile grouting, comprising a tunnel structure, an inclined pile group and a reinforcement area, characterized in that: The inclined pile group includes a plurality of left-side inclined piles and right-side inclined piles, which are respectively located in the soil layers on both sides of the tunnel structure and are symmetrically or asymmetrically distributed. The left-side inclined piles and the right-side inclined piles are spaced a certain distance apart and cross each other at the bottom of the tunnel structure. The reinforcement area is an area reinforced by grouting, located between the tunnel structure and the inclined pile group, and includes a bottom reinforcement area and a side reinforcement area. The bottom reinforcement area is located between the intersection area of ​​the left inclined pile and the right inclined pile and the bottom of the tunnel structure, and the side reinforcement area is located between the left inclined pile and the right inclined pile and the two sides of the tunnel structure. The preliminary parameters of the length, diameter and inclination angle of the inclined pile are determined by calculation using formula (1): ； Q uk ——vertical bearing capacity of inclined piles; Q sk ——Standard value of total limit pile side soil friction resistance in non-vertical grouting section; Q gsk ——Standard value of total limit pile side soil friction resistance in vertical grouting section; Q gpk ——Standard value of total ultimate bearing capacity of pile bottom and pile body soil layer; d ——diameter of inclined pile; α ——inclination angle of inclined pile; l ——length of inclined pile; l j ——The inclined pile is located at j The vertical height of the non-grouting section in the soil layer; l gi ——The inclined pile is located at i The vertical height of the grouting section in the soil layer; l ——length of inclined pile, l=l j / sin α + l gi / sin α ; q sik , q sjk , q pk ——respectively grouting section i The standard value of the friction resistance of the soil at the pile side of the initial limit soil layer, the non-grouting section i The standard value of soil resistance at the initial limit pile side, and the standard value of bearing capacity of soil at the initial limit pile bottom and pile body; β si , β p ——respectively represent the friction resistance of the soil at the side of the pile, and the bearing capacity enhancement coefficient of the soil layer at the bottom of the pile and the pile body; Therefore, the inclined pile group composed of multiple inclined piles can effectively keep the reinforcement area between the tunnel structure and the inclined pile group stable and prevent deformation, forming an inclined pile grouting reinforcement tunnel disease control structure.

2. The inclined pile grouting reinforcement type tunnel disease control structure according to claim 1 is characterized in that: A pre-buried grouting system is provided inside the left-side inclined pile and the right-side inclined pile, and the pre-buried grouting system includes a main grouting pipe extending from the pile top to the pile bottom and side grouting pipes spaced apart on both sides of the main grouting pipe and extending out from the pile wall, so that the pile bottom and pile side are respectively reinforced by secondary grouting through the pre-buried grouting system, so that a pile bottom expansion area is formed through the bottom of the main grouting pipe, and a pile side expansion area is formed toward both sides of the pile wall through the side grouting pipe, so as to effectively increase the bearing capacity of the inclined pile and improve the safety performance and pressure bearing performance.

3. The inclined pile grouting reinforcement type tunnel disease control structure according to claim 1 is characterized in that: The left-side inclined piles and the right-side inclined piles are arranged in sequence along the longitudinal direction of the tunnel structure, cross each other just below the tunnel structure, and there is a certain distance between adjacent piles.

4. The inclined pile grouting reinforcement tunnel disease treatment structure according to claim 1, characterized in that: When using ground drilling and grouting, first drill inclined holes from the ground along the left and right inclined piles to the bottom reinforcement area, insert the bottom grouting pipe, and at the same time grouting reinforcement to the bottom reinforcement area; after the grouting reinforcement of the bottom reinforcement area is completed, drill vertical holes from the ground to the side reinforcement area, insert the side grouting pipe for grouting reinforcement, and grouting should be evenly applied to both sides of the bottom reinforcement area and the side reinforcement area at the same time to avoid deformation of the tunnel structure due to uneven grouting pressure.

5. A construction method for a tunnel disease treatment structure reinforced by inclined pile grouting as claimed in any one of claims 1 to 4, characterized in that The steps include: Step 1: Obtain the tunnel structure coordinates, burial depth, diameter, and deformation parameters of the area to be reinforced; Step 2: Determine the drilling points on the ground according to the location of the tunnel structure and the design parameters of the inclined piles; Based on the confirmed inclined pile design parameters, the horizontal distance between the tunnel structure and the ground drilling point is calculated by formula (2): x ; （2） x - the horizontal distance between the tunnel structure and the ground drilling point; h - depth of tunnel structure; r - radius of the tunnel structure; d 3 – Clear distance between tunnel structure and inclined piles; Step 3: After the inclined pile group is constructed, secondary grouting is performed at the pile bottom and pile side through the main grouting pipe and side grouting pipe of the pre-buried grouting system in the inclined pile group to form a pile bottom expansion area and a pile side expansion area, thereby achieving the expansion of the pile bottom and pile side and improving the grouting effect; Step 4: Grouting is carried out inside the tunnel structure or by drilling holes on the ground into the reinforcement area.

6. The construction method of the inclined pile grouting reinforcement type tunnel disease treatment structure according to claim 5, characterized in that: When ground drilling and grouting is adopted, grouting reinforcement is carried out by drilling inclined holes around the left and right inclined piles and inserting the bottom grouting pipes respectively. There is no obstruction above the side reinforcement area, and vertical holes are drilled directly from the ground and grouting reinforcement is carried out on the side reinforcement area through the side grouting pipes.

7. The construction method of the inclined pile grouting reinforcement type tunnel disease treatment structure according to claim 6, characterized in that: A casing with an inner diameter larger than the drill bit is set at the mouth of the inclined hole. The casing stabilizes the wall of the inclined hole to prevent the hole from collapsing, assists the drill bit in guiding when entering the soil, and controls the inclination angle of the inclined hole. The length of the casing extends to the bottom of the hole and is gradually pulled out as the concrete is subsequently penetrated. Long guide cylinders are arranged at a certain interval on the drill rod, the drill rod is located in the center of the guide cylinder, and both ends of the guide cylinder are arranged to be tapered. On the one hand, the drill rod is controlled to always be located in the center of the inclined hole to avoid hole position deviation; on the other hand, the tapered mouth helps the drill rod to move smoothly in the inclined hole.

8. The construction method of the inclined pile grouting reinforcement type tunnel disease treatment structure according to claim 6, characterized in that: A guide bracket is arranged on the catheter to ensure that the catheter is located in the center of the left oblique hole and the right oblique hole.

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