Pile unit directional reinforcing method and device for layered rock mass stratum tunnel inverted arch

Abstract

The invention provides a pile unit directional reinforcing method and device for a layered rock mass stratum tunnel inverted arch, and relates to the technical field of tunnels and underground engineering. The method comprises the steps that parameter information of each tunnel section of a layered rock mass stratum tunnel is obtained; working condition information about the large deformation grade and the bedding angle is constructed according to parameters to be optimized, wherein the parameters to be optimized comprise the pile length, the arrangement angle and the arrangement position of the pile unit; constructing a numerical model of the stratified rock mass stratum tunnel according to the parameter information; parameter optimization is conducted through the working condition information and the numerical model, and an optimal pile unit directional reinforcement scheme is obtained; and adjusting the optimal pile unit directional reinforcement scheme to obtain final schemes under different large deformation grades, and performing pile unit directional reinforcement through the final schemes and the large deformation grade of each tunnel section. The problem that an ideal reinforcing effect is difficult to achieve when a traditional tunnel inverted arch reinforcing method is used for coping with a large deformation disaster of a stratified rock mass stratum is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnels and underground engineering, and in particular to a method and device for directional reinforcement of pile units of an inverted arch of a tunnel in layered rock strata. Background Art

[0002] In nature, rocks, especially sedimentary and metamorphic rocks, often develop internally oriented weak surfaces such as bedding, foliation, and schistosity due to sedimentation or metamorphism during diagenesis. The existence of these weak surfaces has a significant impact on geotechnical engineering, especially underground engineering. Bedding weak surfaces in rock masses directly affect the mechanical behavior of underground engineering structures, potentially leading to large deformations in key locations such as tunnel inverts.

[0003] Traditional reinforcement methods, such as grouting and pile support, often fail to achieve ideal reinforcement results when addressing large deformations in layered rock formations. While grouting can fill weak points, it struggles to fundamentally alter the mechanical properties of the rock mass and improve the asymmetric deformation characteristics of layered rock masses. Pile support, however, may not only fail to provide effective support due to the presence of bedding planes, but may also cause unnecessary disturbance of the surrounding rock mass. Therefore, a more effective and targeted reinforcement method is needed to address this issue and effectively reinforce and protect the tunnel invert. Summary of the Invention

[0004] The present invention aims to provide a method and apparatus for directional reinforcement of pile units in a tunnel invert in layered rock mass to improve the above-mentioned problem. To achieve the above-mentioned object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present application provides a method for directional reinforcement of pile units of an inverted arch of a tunnel in a layered rock mass stratum, comprising:

[0006] Acquiring parameter information of each tunnel section of a layered rock stratum tunnel, wherein the parameter information includes surrounding rock information, surrounding rock change information, invert arch change information, and large deformation level;

[0007] constructing working condition information about large deformation levels and bedding angles based on quasi-optimization parameters, wherein the quasi-optimization parameters include pile length, arrangement angle, and arrangement position of the pile unit;

[0008] Construct a numerical model of a tunnel in layered rock mass based on parameter information;

[0009] Parameter optimization is performed through working condition information and numerical models to obtain the optimal pile unit directional reinforcement scheme;

[0010] The optimal pile unit directional reinforcement scheme is adjusted to obtain the final scheme under different large deformation levels. The pile unit directional reinforcement is carried out based on the final scheme and the large deformation level of each tunnel section.

[0011] In a second aspect, the present application further provides a pile unit directional reinforcement device for a tunnel invert in a layered rock mass stratum, comprising:

[0012] an acquisition module for acquiring parameter information of each tunnel section of a layered rock stratum tunnel, wherein the parameter information includes surrounding rock information, surrounding rock change information, invert arch change information, and large deformation level;

[0013] a working condition construction module for constructing working condition information on large deformation level and bedding angle based on quasi-optimization parameters, wherein the quasi-optimization parameters include pile length, arrangement angle, and arrangement position of the pile unit;

[0014] A model building module is used to build a numerical model of a tunnel in layered rock mass based on parameter information;

[0015] The optimization module is used to optimize parameters based on working condition information and numerical models to obtain the optimal pile unit directional reinforcement solution;

[0016] The adjustment module is used to adjust the optimal pile unit directional reinforcement scheme to obtain the final scheme under different large deformation levels, and to perform pile unit directional reinforcement based on the final scheme and the large deformation level of each tunnel section.

[0017] The beneficial effects of the present invention are as follows: the present invention establishes a numerical model of geological-mechanical coupling based on bedding attitude, and by constructing comprehensive performance indicators, combining ground stress inversion and particle swarm algorithm to optimize the parameters of pile unit reinforcement, a scientific and accurate support effect is achieved. At the same time, the influence of large deformation level and bedding angle on the directional reinforcement of layered rock strata is taken into consideration, and through accurate geological survey, surrounding rock change monitoring and large deformation level determination and precise pile unit construction control, effective reinforcement and protection of tunnel inverts are achieved. At the same time, it is applicable to tunnels in different layered rock formations, and while achieving effective reinforcement of tunnel inverts, it can reduce unnecessary disturbances to the base surrounding rock, improve the safety and stability of tunnel construction, and provide a scientific and reliable technical solution for large deformation control of layered rock formation tunnels.

[0018] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the embodiments of the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the process of the pile unit directional reinforcement method for the inverted arch of a tunnel in layered rock strata according to an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of directional reinforcement of pile units with different bedding inclination angles under slight large deformation in an embodiment of the present invention;

[0022] Figure 3 Schematic diagram of directional reinforcement of pile units with different bedding inclination angles under moderate to large deformation in an embodiment of the present invention;

[0023] Figure 4 Schematic diagram of directional reinforcement of pile units with different bedding inclination angles under severe large deformation in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are used only to distinguish the description and should not be understood as indicating or implying relative importance.

[0026] Example 1:

[0027] This embodiment provides a method for directional reinforcement of pile units in a tunnel invert in layered rock strata.

[0028] See also Figure 1, the figure shows that the method includes step S100, step S200, step S300, step S400, and step S500.

[0029] Step S100: Acquire parameter information of each tunnel section of a layered rock stratum tunnel, wherein the parameter information includes surrounding rock information, surrounding rock change information, invert arch change information, and large deformation level;

[0030] In this embodiment, a directional reinforcement method for pile units is obtained based on the condition that the bedding direction is parallel to or intersects the tunnel excavation direction at a small angle.

[0031] In step S100, the steps for obtaining parameter information are:

[0032] Step S101: Conducting geological surveys on each tunnel section of a layered rock stratum tunnel to obtain surrounding rock information and surrounding rock change information, wherein the surrounding rock information includes bedding plane parameters, mechanical parameters of the rock mass, and groundwater parameters;

[0033] Step S102: Setting monitoring points on the inverted arch structure in each tunnel section during the construction process, and obtaining the deformation of the inverted arch structure during the construction process through the monitoring points;

[0034] Step S103: calculating inverted arch change information based on the deformation amount, wherein the inverted arch change information includes the inverted arch deformation rate and the inverted arch cumulative deformation amount;

[0035] Step S104: Classify the large deformation levels according to the deformation rate of the inverted arch and the cumulative deformation of the inverted arch to obtain the large deformation level of each tunnel section.

[0036] In this embodiment, the bedding plane parameters include parameters such as the bedding plane inclination and bedding plane strike. Among them, the inclination (angle with the horizontal plane) and strike (direction of layer extension) of the rock bedding are measured by a geological compass. The groundwater parameters include parameters such as the degree of groundwater development. The mechanical parameters of the rock mass are obtained by conducting in situ stress tests and rock mechanics tests, including elastic modulus, Poisson's ratio, cohesion, internal friction angle, joint shear strength, etc.

[0037] Tunnel deformation can be recorded daily using a total station, GPS measurement system, or fixed benchmarks to determine the invert deformation rate. During tunnel construction, the cumulative deformation of the tunnel invert, measured by cumulative displacement at the monitoring points, can be used to determine the total deformation of the tunnel invert, also known as the cumulative invert deformation.

[0038] At the same time, the deformation rate and cumulative deformation of the inverted arch are used to classify the large deformation grades, which include no large deformation, slight large deformation, moderate large deformation, and strong large deformation, as shown in Table 1, where V represents the deformation rate of the inverted arch and U represents the cumulative deformation of the inverted arch.

[0039] Table 1 Classification of large deformation levels

[0040] Large deformation level Invert deformation rate (mm / d) Cumulative deformation of inverted arch (mm) No major deformation V<1 U<70 Slightly large deformation Ⅰ 1<V<10 70<U<130 Medium-large deformation II 10<V<30 130<U<230 Severe large deformation III 30<V<50 230<U<330

[0041] When the large deformation level is no large deformation, there is no need for directional reinforcement of pile units. And when the deformation rate and cumulative deformation of the inverted arch belong to different levels, reinforcement is usually performed according to the higher large deformation level. For example, when V = 12mm / d and U = 120mm, it is a medium large deformation.

[0042] Step S200: constructing working condition information on large deformation level and bedding angle according to pseudo-optimization parameters, wherein the pseudo-optimization parameters include pile length, arrangement angle, and arrangement position of the pile unit;

[0043] In this embodiment, the working condition factors include three large deformation levels, bedding inclination, pile length, arrangement angle and arrangement position of the pile unit. The working condition information is shown in Table 2.

[0044] Table 2 Working condition information table

[0045]

[0046] To facilitate construction and utilize existing commercially available pile units, pile lengths are rounded to integers, with a working condition set for every 1m of pile length. For short piles, micropiles with lengths of 1-3m and steel pipe piles with lengths of 3-6m are available. The arrangement angles range from 30° to 90°, with a working condition set every 15°.

[0047] Regarding placement, specifically, for slightly large deformations, piles can be omitted from the sidewalls for 0° bedding. For other bedding angles, piles are placed only on the left and right lower sidewalls and invert. For moderately large deformations, piles can be omitted from the sidewalls for 0° bedding. For other conditions, the pile spacing must be ≥ 2 times the pile diameter, with three conditions of 2, 3, and 4 times the pile diameter being used. For severely large deformations, piles can be omitted from the sidewalls for 0° bedding. For other conditions, the pile spacing must be ≥ 2 times the pile diameter, with three conditions of 2, 3, and 4 times the pile diameter being used. The above conditions can be configured based on actual needs.

[0048] Step S300: constructing a numerical model of a tunnel in layered rock mass strata according to parameter information;

[0049] In step S300, the steps of constructing the numerical model are:

[0050] Step S301: establishing a numerical model based on the geometric parameters of the tunnel in the layered rock mass stratum;

[0051] Step S302: obtaining the initial geostress field of the numerical model through surrounding rock change information;

[0052] Step S303: performing in-situ stress inversion on the large deformation level using surrounding rock information and invert arch change information to obtain the boundary stress corresponding to the large deformation level, and determining the boundary conditions of the numerical model based on the boundary stress;

[0053] Step S304: simulating the layered rock mass using the surrounding rock information and the ubiquitous joint constitutive model, setting the bedding plane dip and strike based on the surrounding rock information, and setting the rock mass constitutive model;

[0054] Step S305: constructing a pile unit model, embedding the pile unit model into the grid of the numerical model, and setting pile-rock contact surface parameters.

[0055] In this embodiment, the geometric parameters of the layered rock stratum tunnel are first measured to establish a geometric numerical model. The surrounding rock change information is then used as the preliminary input parameter of the numerical simulation to establish the initial ground stress field of the numerical model to reflect the constitutive characteristics of the surrounding rock. Then, through inversion analysis, the boundary stress borne by the surrounding rock when large deformation occurs is calculated, and the on-site deformation is matched through numerical adjustment to be closer to the actual deformation situation. A pervasive joint constitutive model is used to simulate the layered rock mass so that it reflects the anisotropy of the actual rock strata. According to the surrounding rock information, the inclination and strike of the bedding plane are set to ensure that the rock mass structure conforms to the actual situation, a suitable rock mass constitutive model is selected, and the mechanical parameters of the corresponding rock mass are assigned. At the same time, the pile unit is embedded in the rock mass grid in the numerical model as a special structural unit, and the interaction is simulated by the interface spring. Therefore, a pile unit model is established, and the pile unit model is coupled and embedded while keeping the original grid in the numerical model unchanged.

[0056] Step S400: Optimizing parameters based on working condition information and numerical models to obtain an optimal pile unit directional reinforcement solution;

[0057] The step S400 includes:

[0058] Step S401: selecting at least one representative tunnel segment;

[0059] In this embodiment, the tunnel site area of ​​a layered rock stratum tunnel can be selected as a representative tunnel section. When the rock formation of the tunnel section is stable compared to that of the tunnel site area, the mechanical parameters are within the allowable fluctuation range, and there is no sudden structural change, the tunnel site area can be used to represent the corresponding tunnel section.

[0060] Step S402: setting constraints based on operating condition information and constructing comprehensive performance indicators;

[0061] In this embodiment, converting the working condition information into constraint conditions is actually quantifying the text description into model parameters, that is, mechanical boundaries and calculation rules that can be identified by the numerical model, which facilitates calculation during parameter optimization.

[0062] In step S402, constructing a comprehensive performance index includes:

[0063] Step A100: constructing an inverted arch deformation control index based on the normal deformation of the inverted arch after directional reinforcement and the normal deformation of the inverted arch before directional reinforcement;

[0064] Step A200: constructing an inverted arch stress safety index by using the axial force of the rear inverted arch after the directional reinforcement, the axial force of the front inverted arch after the directional reinforcement, the bending moment of the rear inverted arch after the directional reinforcement, and the bending moment of the front inverted arch after the directional reinforcement;

[0065] Step A300: constructing a plastic zone suppression index based on the volume of the plastic zone after directional reinforcement and the volume of the plastic zone before directional reinforcement;

[0066] Step A400: constructing a comprehensive performance index through the inverted arch deformation control index, the inverted arch stress safety index and the plastic zone suppression index.

[0067] In this embodiment, a comprehensive performance index is constructed by analyzing and comparing the deformation of the inverted arch, the deformation of the surrounding rock mass, the stress on the inverted arch, and the size of the plastic zone. The comprehensive performance index is normalized to a dimensionless value. The calculation formula for the comprehensive performance index is:

[0068] F=ω1·F1+ω2·F2+ω3·F3

[0069]

[0070]

[0071] Where F represents the comprehensive performance index, ω1, ω2, and ω3 represent weight parameters, F1 represents the inverted arch deformation control index, F2 represents the inverted arch stress safety index, and F3 represents the plastic zone suppression index.

[0072] Step S403: For each representative tunnel segment, with the goal of minimizing the comprehensive performance index, particle swarm optimization is performed based on constraints and numerical models to obtain the optimal pile unit directional reinforcement scheme for each representative tunnel segment under different large deformation levels and different bedding angles.

[0073] In step S403, the steps for obtaining the optimal pile unit directional reinforcement scheme under different large deformation levels and different bedding angles are as follows:

[0074] Step B100: for each representative tunnel section, obtain combinations of different large deformation levels and different bedding angles based on working condition information;

[0075] Step B200: for each combination, initialize multiple particles, each particle representing a set of parameters to be optimized;

[0076] Step B300: Inputting parameter information of the representative tunnel section and each particle into the numerical model to simulate tunnel excavation, and obtaining unreinforced simulation results and reinforced simulation results;

[0077] Step B400: Perform iterative optimization based on the unreinforced simulation results and the reinforced simulation results to obtain the optimal pile unit directional reinforcement scheme under different combinations of each representative tunnel section.

[0078] In step B400, iterative optimization is performed using the unreinforced simulation results and the reinforced simulation results, including:

[0079] Step B401: Calculating the first comprehensive performance index of each particle based on the unreinforced simulation results and the reinforced simulation results;

[0080] Step B402: updating the particles using the update formula, and calculating the second comprehensive performance index using the updated particles and the numerical model;

[0081] Step B403: Select the smaller value between the first comprehensive performance index and the second comprehensive performance index, and update the individual optimal solution and the global optimal solution of the particle by the smaller value;

[0082] Step B404: Determine whether the stopping condition is met. If so, select the global optimal solution as the optimal pile unit directional reinforcement scheme. Otherwise, use the smaller value as the first comprehensive performance indicator for the next round of iteration and proceed to the next round of iteration.

[0083] Step S500: adjusting the optimal pile unit directional reinforcement scheme to obtain a final scheme under different large deformation levels, and performing pile unit directional reinforcement according to the final scheme and the large deformation level of each tunnel section.

[0084] In this example, after obtaining the optimal pile unit directional reinforcement scheme for each representative tunnel section under different large deformation levels and different bedding angles, a standardized analysis of support parameters was performed to obtain the relationship between the arrangement angle and the bedding angle. Multiple decision dimensions were compressed to obtain the final scheme, as shown in Table 3, where I indicates slightly large deformation, II indicates moderately large deformation, and III indicates strongly large deformation.

[0085] Table 3 Final solution for directional reinforcement at different large deformation levels

[0086]

[0087]

[0088] The final solution, shown in Table 3, allows for flexible adjustment of the pile unit directional reinforcement scheme for different tunnel sections in layered rock strata for targeted support. Moreover, by simply monitoring the maximum deformation level and bedding angle of each tunnel section, a corresponding reinforcement scheme can be quickly developed for directional reinforcement. This improves the existing pile unit reinforcement method, which may not only fail to provide support due to the presence of bedding planes but also cause unnecessary disturbance of the surrounding rock.

[0089] At the same time, the type of pile unit can be freely selected according to the actual situation and needs of the project, including but not limited to the following: micro piles, rotary jet piles, steel pipe piles, and cast-in-place piles.

[0090] The reinforcement scheme in Table 3 can also be applied to tunnels in other layered rock formations. After designing the actual reinforcement scheme based on Table 3 and the large deformation level, the directional reinforcement scheme for pile units is compared with the non-directional reinforcement scheme through FLAC3D numerical simulation to verify the effectiveness of the directional reinforcement before construction.

[0091] Example 2:

[0092] In this embodiment, geological exploration is carried out on the tunnel site of a certain layered rock stratum tunnel A. The tunnel site is mainly composed of carbonaceous slate, and the bedding surface inclinations are mainly 0°, 30°, 45°, 60°, and 90°. The bedding strike is parallel to the tunnel excavation direction. It belongs to Class IV surrounding rock with poor rock properties, BQ=247.5, KV=0.55, RC=20Mpa, and groundwater development. Among them, BQ represents the basic quality index of rock mass, KV represents the rock mass integrity coefficient, and RC represents the saturated uniaxial compressive strength of rock.

[0093] The deformation rate and cumulative deformation of the tunnel invert arch during the construction process were measured, which were V=8mm / d and U=84mm respectively. It was judged that the tunnel site area had slight large deformation.

[0094] The scheme design was carried out based on the final scheme in Table 3. The pile unit type was selected as micro pile, with a pile diameter of 100 mm and a pile length of 6 m. The pile units were arranged at the left and right lower side walls and the left and right arch feet. The pile unit arrangement angles were arranged according to the five bedding angles of 0°, 30°, 45°, 60°, and 90° in the tunnel site. The side walls were arranged horizontally, the left and right arch feet were arranged perpendicular to the bedding along the inclination side, and the left and right arch feet were arranged plumb against the inclination side. In addition, no pile units were set on the side walls for 0° bedding. The specific arrangement method is as follows: Figure 2 shown.

[0095] After designing the reinforcement scheme, FLAC3D numerical simulation was used to compare the directional reinforcement scheme of the pile unit with the non-directional reinforcement scheme to verify the effect of the directional reinforcement. After determining the effectiveness and rationality of the directional reinforcement scheme, construction was carried out.

[0096] In this embodiment, geological exploration is carried out on the tunnel site of a certain layered rock formation tunnel B. The tunnel site is mainly composed of thin-layered sericite phyllite, and the bedding surface dips are mainly 0°, 30°, 45°, 60°, and 90°. The bedding strike is parallel to the tunnel excavation direction. It belongs to Class V surrounding rock with poor rock properties, BQ=154, KV=0.4, RC=4.5MPa, and no groundwater.

[0097] The deformation rate and cumulative deformation of the tunnel invert arch were measured during the construction process. The V and U in different sections of the tunnel site were different, namely V = 27 mm / d, U = 227 mm and V = 33 mm / d, U = 267 mm, respectively. It was judged that the tunnel site included moderate large deformation and severe large deformation.

[0098] The final scheme in Table 3 is used for the scheme design. In the medium-large deformation section of the inverted arch, the pile unit type is selected as a cast-in-place pile with a pile diameter of 100mm and a pile length of 6m and 9m. The pile units are arranged at the left and right lower side walls and the inverted arch. The pile unit arrangement angles are arranged according to five bedding angles: 0°, 30°, 45°, 60°, and 90°. The pile units need to be arranged in a combination of long and short. The side walls are arranged horizontally, the inverted arch is arranged perpendicular to the bedding on the inclined side, and the inverted arch is arranged plumb on the reverse inclined side. Pile units are not required on the side walls for 0° bedding. The specific arrangement method is as follows: Figure 3 shown.

[0099] In the strong deformation section of the inverted arch, the pile unit type is selected as steel pipe pile, the pile diameter is 220mm, the pile length is selected as 9m, the pile unit is arranged at the left and right lower side walls and the inverted arch, the pile unit arrangement angle is arranged according to five bedding angles of 0°, 30°, 45°, 60°, and 90°, the side wall is arranged horizontally, the inverted arch is arranged perpendicular to the bedding along the inclination side, and the inverted arch is arranged with a plumb bob. Pile units are not required on the side wall for 0° bedding. The specific arrangement method is as follows: Figure 4 shown.

[0100] After designing the reinforcement scheme, FLAC3D numerical simulation software was used to compare the pile unit directional reinforcement scheme with the non-directional reinforcement scheme. Construction was carried out after verifying the effect of the directional reinforcement.

[0101] During construction, to ensure the proper arrangement angle of the pile units, auxiliary measures must be taken to control the drilling angle when drilling with a drilling rig. When staking out the pile positions, a total station or high-precision RTK is used to precisely locate the pile holes, ensuring that the pile positions meet the design requirements. Site markers are also set at the positioning points to facilitate construction personnel in quickly locating the pile positions in subsequent work. Common positioning methods include driving steel bars and filling them with white lime, or marking the pile positions on the ground with spray paint or coatings, using steel bars or wooden stakes as physical markers. After the pile driver is in place, an instrument is used to align the pile position to ensure the verticality of the drill rod. Check that the rim of the lifting pulley, the hole for securing the drill rod, and the center of the casing are aligned on the same axis to ensure the pile body remains vertical during piling.

[0102] In summary, the present invention provides a highly targeted and adaptable method for directional reinforcement of pile units for tunnel inverts in layered rock formations subjected to varying degrees of large deformation. Through meticulous geological surveys and monitoring of surrounding rock changes, combined with the determination of large deformation levels, the type, length, layout, and angle of the pile units can be accurately selected and designed, effectively reinforcing the tunnel invert while minimizing unnecessary disturbance to the underlying surrounding rock. Comparative verification using FLAC3D numerical simulations ensured the effectiveness and rationality of the directional reinforcement scheme, further enhancing the safety and stability of tunnel construction.

[0103] Example 3:

[0104] This embodiment provides a device for directional reinforcement of pile units in a tunnel invert in a layered rock mass stratum, the device comprising:

[0105] an acquisition module for acquiring parameter information of each tunnel section of a layered rock stratum tunnel, wherein the parameter information includes surrounding rock information, surrounding rock change information, invert arch change information, and large deformation level;

[0106] a working condition construction module for constructing working condition information on large deformation level and bedding angle based on quasi-optimization parameters, wherein the quasi-optimization parameters include pile length, arrangement angle, and arrangement position of the pile unit;

[0107] A model building module is used to build a numerical model of a tunnel in layered rock mass based on parameter information;

[0108] The optimization module is used to optimize parameters based on working condition information and numerical models to obtain the optimal pile unit directional reinforcement solution;

[0109] The adjustment module is used to adjust the optimal pile unit directional reinforcement scheme to obtain the final scheme under different large deformation levels, and to perform pile unit directional reinforcement based on the final scheme and the large deformation level of each tunnel section.

[0110] The model building module includes:

[0111] A first construction unit is used to establish a numerical model using geometric parameters of a tunnel in layered rock mass;

[0112] The second construction unit is used to obtain the initial ground stress field of the numerical model through the surrounding rock change information;

[0113] The inversion unit is used to perform ground stress inversion on the large deformation level based on the surrounding rock information and the invert arch change information, obtain the boundary stress corresponding to the large deformation level, and determine the boundary conditions of the numerical model based on the boundary stress;

[0114] The third construction unit is used to simulate the layered rock mass through the surrounding rock information and the pervasive joint constitutive model, set the bedding plane dip and strike according to the surrounding rock information, and set the rock mass constitutive model;

[0115] The fourth construction unit is used to construct a pile unit model, embed the pile unit model into the grid of the numerical model, and set pile-rock contact surface parameters.

[0116] The optimization module includes:

[0117] A selection unit, configured to select at least one representative tunnel segment;

[0118] A setting unit is used to set constraints based on working condition information and construct comprehensive performance indicators;

[0119] The optimization unit is used to perform particle swarm optimization based on constraints and numerical models for each representative tunnel section, with the goal of minimizing the comprehensive performance index, to obtain the optimal pile unit directional reinforcement scheme for each representative tunnel section under different large deformation levels and different bedding angles.

[0120] It should be noted that, regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated on here.

[0121] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0122] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for directional reinforcement of pile units of tunnel inverts in layered rock strata, characterized in that: include: Acquiring parameter information of each tunnel section of a layered rock stratum tunnel, wherein the parameter information includes surrounding rock information, surrounding rock change information, invert arch change information, and large deformation level; constructing working condition information about large deformation levels and bedding angles based on quasi-optimization parameters, wherein the quasi-optimization parameters include pile length, arrangement angle, and arrangement position of the pile unit; Construct a numerical model of a tunnel in layered rock mass based on parameter information; Parameter optimization is performed through working condition information and numerical models to obtain the optimal pile unit directional reinforcement scheme; The optimal pile unit directional reinforcement scheme is adjusted to obtain the final scheme under different large deformation levels. The pile unit directional reinforcement is carried out based on the final scheme and the large deformation level of each tunnel section.

2. The method for directional reinforcement of pile units in layered rock stratum tunnel inverts according to claim 1, characterized in that , the steps for obtaining the parameter information are: Conducting geological surveys on each tunnel section of a tunnel in layered rock mass to obtain surrounding rock information and surrounding rock change information, including bedding plane parameters, rock mass mechanical parameters, and groundwater parameters; During the construction process, monitoring points are set up in the inverted arch structure of each tunnel section, and the deformation of the inverted arch structure during the construction process is obtained through the monitoring points; Calculating inverted arch change information based on the deformation amount, wherein the inverted arch change information includes the inverted arch deformation rate and the inverted arch cumulative deformation amount; The maximum deformation grade of each tunnel section is obtained by dividing the maximum deformation grade into categories based on the deformation rate of the inverted arch and the cumulative deformation of the inverted arch.

3. The method for directional reinforcement of pile units of a tunnel invert in layered rock mass according to claim 1, characterized in that ,The steps of constructing the numerical model are: Establishing numerical models through geometric parameters of tunnels in layered rock formations; The initial ground stress field of the numerical model is obtained through the surrounding rock change information; The ground stress inversion of the large deformation level is carried out based on the surrounding rock information and the invert arch change information to obtain the boundary stress corresponding to the large deformation level, and the boundary conditions of the numerical model are determined based on the boundary stress. Simulate layered rock mass through surrounding rock information and pervasive joint constitutive model, set bedding plane dip and strike based on surrounding rock information, and set rock mass constitutive model; Construct a pile unit model, embed the pile unit model into the grid of the numerical model, and set the pile-rock contact surface parameters.

4. The method for directional reinforcement of pile units of a tunnel invert in layered rock mass according to claim 1, characterized in that ,The parameter optimization is performed through the working condition information and the numerical model to obtain the optimal pile unit directional reinforcement scheme, including: selecting at least one representative tunnel section; Set constraints based on operating condition information and build comprehensive performance indicators; For each representative tunnel section, with the goal of minimizing the comprehensive performance index, particle swarm optimization is performed based on constraints and numerical models to obtain the optimal pile unit directional reinforcement scheme for each representative tunnel section under different large deformation levels and different bedding angles.

5. The method for directional reinforcement of pile units of a tunnel invert in layered rock mass according to claim 4, characterized in that ,The construction of comprehensive performance indicators includes: The deformation control index of the inverted arch is constructed by the normal deformation of the inverted arch after directional reinforcement and the normal deformation of the inverted arch before directional reinforcement. The force safety index of the inverted arch is constructed by the axial force of the inverted arch after directional reinforcement, the axial force of the inverted arch before directional reinforcement, the bending moment of the inverted arch after directional reinforcement and the bending moment of the inverted arch before directional reinforcement. The plastic zone suppression index is constructed by the volume of the plastic zone after directional reinforcement and the volume of the plastic zone before directional reinforcement; Comprehensive performance indicators are constructed through the inverted arch deformation control index, inverted arch stress safety index and plastic zone inhibition index.

6. The method for directional reinforcement of pile units in layered rock stratum tunnel inverts according to claim 5, characterized in that ,The steps for obtaining the optimal pile unit directional reinforcement scheme under different large deformation levels and different bedding angles are as follows: For each representative tunnel section, combinations of different large deformation levels and different bedding angles are obtained based on the working condition information; For each combination, a plurality of particles are initialized, each particle representing a set of parameters to be optimized; The parameter information of the representative tunnel section and each particle are input into the numerical model to simulate tunnel excavation, and the simulation results without reinforcement and with reinforcement are obtained. By iteratively optimizing the unreinforced and reinforced simulation results, the optimal pile unit directional reinforcement scheme under different combinations of each representative tunnel section is obtained.

7. The method for directional reinforcement of pile units in layered rock stratum tunnel inverts according to claim 6, characterized in that ,The iterative optimization through the unreinforced simulation results and the reinforced simulation results includes: Calculate the first comprehensive performance index of each particle through the unreinforced simulation results and the reinforced simulation results; updating the particles using an updating formula, and calculating a second comprehensive performance index using the updated particles and the numerical model; Selecting the smaller value of the first comprehensive performance index and the second comprehensive performance index, and updating the individual optimal solution and the global optimal solution of the particle by the smaller value; It is determined whether the stopping condition is met. If so, the global optimal solution is selected as the optimal pile unit directional reinforcement scheme. Otherwise, the smaller value is used as the first comprehensive performance indicator of the next round of iteration and the next round of iteration is carried out.

8. A device for directional reinforcement of pile units for tunnel inverts in layered rock mass, characterized in that: include: an acquisition module for acquiring parameter information of each tunnel section of a layered rock stratum tunnel, wherein the parameter information includes surrounding rock information, surrounding rock change information, invert arch change information, and large deformation level; a working condition construction module for constructing working condition information on large deformation level and bedding angle based on quasi-optimization parameters, wherein the quasi-optimization parameters include pile length, arrangement angle, and arrangement position of the pile unit; A model building module is used to build a numerical model of a tunnel in layered rock mass based on parameter information; The optimization module is used to optimize parameters based on working condition information and numerical models to obtain the optimal pile unit directional reinforcement solution; The adjustment module is used to adjust the optimal pile unit directional reinforcement scheme to obtain the final scheme under different large deformation levels, and to perform pile unit directional reinforcement based on the final scheme and the large deformation level of each tunnel section.

9. The device for directional reinforcement of pile units for inverted arches of layered rock strata tunnels according to claim 8, characterized in that: The model building module includes: A first construction unit is used to establish a numerical model using geometric parameters of a tunnel in layered rock mass; The second construction unit is used to obtain the initial ground stress field of the numerical model through the surrounding rock change information; The inversion unit is used to perform ground stress inversion on the large deformation level based on the surrounding rock information and the invert arch change information, obtain the boundary stress corresponding to the large deformation level, and determine the boundary conditions of the numerical model based on the boundary stress; The third construction unit is used to simulate the layered rock mass through the surrounding rock information and the pervasive joint constitutive model, set the bedding plane dip and strike according to the surrounding rock information, and set the rock mass constitutive model; The fourth construction unit is used to construct a pile unit model, embed the pile unit model into the grid of the numerical model, and set pile-rock contact surface parameters.

10. The pile unit directional reinforcement device for a layered rock stratum tunnel invert according to claim 8, characterized in that: The optimization module includes: A selection unit, configured to select at least one representative tunnel segment; A setting unit is used to set constraints based on working condition information and construct comprehensive performance indicators; The optimization unit is used to perform particle swarm optimization based on constraints and numerical models for each representative tunnel section, with the goal of minimizing the comprehensive performance index, to obtain the optimal pile unit directional reinforcement scheme for each representative tunnel section under different large deformation levels and different bedding angles.

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