A method for calculating differential settlement of shield segments under a large-height-difference covering soil layer

Abstract

This invention discloses a method for calculating differential settlement of shield tunnel segments under a large elevation difference in overburden, relating to the field of underground engineering and structural safety assessment technology. The method involves establishing a differential settlement calculation function: E represents the deformation modulus of the soil, v represents Poisson's ratio, q represents the additional load from the upper layer, γ represents the unit weight of the overburden layer, and ΔH(x) represents the difference in overburden thickness at location x. This differential settlement calculation function is applicable to predicting uneven settlement of tunnel segments under conditions of large elevation differences in overburden, and can also be used to calculate the settlement of existing tunnel segments caused by surface loading.

Description

Technical Field

[0001] This invention relates to the field of underground engineering and structural safety assessment technology, and in particular to a method for calculating differential settlement of shield tunnel segments under a large elevation difference in overburden. Background Technology

[0002] With the increasing urban population and congested road traffic, accelerating the development of urban underground space and promoting urban rail transit construction has become particularly important. However, shield tunnels still face many difficulties and challenges when traversing complex terrain. Currently, most methods for calculating shield segment settlement are based on the assumption of continuous distribution of the overlying strata and a generally level surface. However, in actual construction, tunnels often pass through areas with significant surface undulations and discontinuous strata distribution. In such cases, shield segments will bear different overlying loads, leading to uneven deformation, which can seriously affect the safe use of the tunnel. Although numerical simulation can accurately predict the settlement of segments at corresponding locations, this method is time-consuming and labor-intensive. Therefore, there is an urgent need for a calculation method that can fully consider significant strata undulations and quickly predict segment settlement. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides a method for calculating the differential settlement of shield tunnel segments under a large elevation difference overburden layer, which is applicable to the prediction of uneven settlement of tunnel segments under conditions where there is a large elevation difference overburden layer.

[0004] To achieve the above objectives, the present invention adopts the following technical solution, including:

[0005] A method for calculating differential settlement of shield tunnel segments under a large elevation difference in overburden is proposed, and a calculation function for differential settlement of tunnel segments is established as follows:

[0006]

[0007] Where ΔS(x) represents the differential settlement value of the tunnel segment at location x, E represents the deformation modulus of the soil, v represents Poisson's ratio, q represents the additional load on the upper part, γ represents the weight of the overburden, and ΔH(x) represents the difference in overburden thickness between location x and the reference point.

[0008] Preferably, a tunnel segment is used as a reference point, and the soil cover thickness at the reference point is recorded. Soil cover thickness variation data is extracted along the tunnel line to obtain the maximum soil cover thickness elevation difference H and its corresponding horizontal distance L. The soil cover thickness difference ΔH(x) between location x and the starting point is:

[0009]

[0010] Wherein, the horizontal distance L represents the horizontal distance from the benchmark point at the point of maximum soil cover thickness difference H, and x represents the horizontal distance from the benchmark point at location x.

[0011] Preferably, if the overlying soil is divided into multiple soil layers, the weight γ of the overlying soil is obtained by weighting the thickness of each soil layer.

[0012] Preferably, if there is no difference in ground elevation but there is ground load, the load is equivalent to the overburden, and the differential settlement value of the segment at the ground load location is calculated according to the segment differential settlement calculation function.

[0013] The present invention also provides a computer program product, characterized in that it includes a computer program / instruction, which, when executed by a processor, implements the aforementioned method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer.

[0014] The present invention also provides a readable storage medium, characterized in that it stores a computer program thereon, which, when executed, implements the aforementioned method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer.

[0015] The present invention also provides an electronic device, characterized in that it includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the aforementioned method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer.

[0016] The advantages of this invention are:

[0017] (1) The calculation formula of this invention takes into account the impact of the increase in overburden load caused by surface backfill on the settlement of the tunnel segments, so that the calculation formula can be adapted to the excavation process of underground tunnels and the application range of the calculation formula is wider.

[0018] (2) The calculation method of the present invention is simple, requires fewer parameters, considers more comprehensive factors, has smaller calculation error, and is more accurate, and has broad application prospects. Attached Figure Description

[0019] Figure 1 This is a comparison chart of the differential settlement of tunnel segments obtained through numerical simulation and formula calculation in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1

[0022] The present invention provides a method for calculating differential settlement of tunnel segments under geological conditions with large elevation differences in overburden, as detailed below:

[0023] Taking the segment unit at the starting point of the shield tunnel as the reference point, and determining the maximum soil cover thickness difference H along the tunnel axis and its corresponding horizontal distance L, the soil cover thickness difference at any location x can be expressed as:

[0024]

[0025] Where x represents the horizontal distance from the reference point at position x, ΔH(x) represents the difference in soil cover thickness between position x and the reference point, and the horizontal distance L represents the horizontal distance from the reference point at the point of maximum soil cover thickness difference H.

[0026] Specifically, firstly, the segment unit at the starting point of the shield tunnel is selected as the reference point, and the thickness of the overburden layer at the reference point is recorded; then, the topographic change data of the overburden layer is determined along the tunnel line, and the maximum overburden thickness difference H and its corresponding horizontal distance L are obtained.

[0027] Based on this, a modified elastic foundation beam model (Modified Winkler) is used to establish a calculation function for the differential settlement of tunnel segments. Assuming the tunnel segments are longitudinally rigid beam elements and the foundation is supported by soil with uniformly distributed elastic reaction coefficients, and considering the load differences in the overburden layers above the segments, the expression for the differential settlement of the tunnel segments at the calculation point is obtained as follows:

[0028]

[0029] Where E represents the soil deformation modulus (MPa); v represents Poisson's ratio (generally taken as 0.3 to 0.4); q represents the additional load from above (kPa); and γ represents the unit weight of the overlying soil (kN / m³). 3 If the overlying soil is multi-layered, the weighted average unit weight of the overlying soil is used, and ΔS(x) represents the differential settlement value of the tunnel segment at any location x.

[0030] Furthermore, if there is no difference in ground elevation but there is ground load, the load is equivalent to the overburden, and the differential settlement value of the segment at the ground load location is calculated according to the segment differential settlement calculation function.

[0031] Example 2

[0032] To explore the general law of the influence of the overlying soil layer elevation difference on the differential settlement of shield tunnel segments, this embodiment simplifies the overlying soil layer in the model into a single soil type, taking clay soil as an example. The soil parameters are shown in Table 1.

[0033] Table 1 Soil layer parameters

[0034]

[0035] In this embodiment, a three-dimensional numerical model of differential settlement of tunnel segments under a large elevation difference overburden layer is established using the finite element software Midas GT / NX. The soil in the model is simulated using the Mohr-Coulomb constitutive model, and the thickness of the overburden layer increases during the tunneling process.

[0036] In this embodiment, the differential settlement of the tunnel segments under different elevation differences on the ground surface is calculated using numerical simulation. The simulated working conditions are shown in Table 2.

[0037] Table 2. Parameters for each operating condition in this embodiment.

[0038]

[0039] For the above-mentioned numerical simulation conditions, the differential settlement values ​​of shield tunnel segments under different elevation differences were calculated using the calculation formula of this invention, and compared with the numerical simulation results. Taking the differential settlement between the segment at 15m of excavation and the initial segment as an example, the elevation difference H of the overburden layer (maximum overburden thickness difference H) under the six conditions are 2.64m, 5.46m, 8.66m, 12.59m, 17.88m, and 25.98m, respectively. The comparison between the calculation results of the formula of this invention and the numerical simulation results is shown below. Figure 1 As shown in the figure, the calculation results of the formula in this invention are in good agreement with the numerical simulation results.

[0040] Example 3

[0041] An electronic device includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method of Embodiment 1 described above.

[0042] The electronic device in this application embodiment may be the mobile device itself, or a standalone device independent of it. The standalone device may communicate with the mobile device to receive the collected input signals from it and send the selected target decision behavior to it.

[0043] An electronic device includes one or more processors and memory. The processor may be a central processing unit (CPU) or other processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. The memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor may execute the program instructions to implement the decision-making behavior and decision-making methods of the various embodiments of this application described above, and / or other desired functions.

[0044] Electronic devices may also include input devices and output devices.

[0045] Example 4

[0046] In addition to the methods and devices described above, embodiments of this application may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the decision-making behavior decision-making method according to various embodiments of this application as described in Embodiment 1 above.

[0047] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0048] Example 5

[0049] Embodiments of this application may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps in the decision-making behavior decision-making method according to various embodiments of this application described in Embodiment 1 above.

[0050] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may, for example, include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calculating the differential settlement of a shield segment under a large-height-difference soil layer, characterized in that, The function for calculating differential settlement of tunnel segments is established as follows: ； in, ΔS ( x ) indicates position x Differential settlement value of the tunnel lining segments at the location, E This represents the deformation modulus of soil; v Indicates Poisson's ratio; q Indicates additional load on the upper part; γ Indicates the weight of the overlying soil. ΔH ( x ) indicates position x Difference in soil cover thickness between the reference point and the benchmark point; Poisson's ratio v The value range is 0.3 to 0.4; Using a tunnel segment as a reference point, the soil cover thickness at the reference point is recorded. Data on the variation of soil cover thickness along the tunnel route is extracted to obtain the maximum soil cover thickness elevation difference. H and its corresponding horizontal distance L ;Location x Difference in soil cover thickness between the starting point and the starting point ΔH ( x )for: ； Among them, horizontal distance L Indicates the maximum difference in soil cover thickness. H The horizontal distance from the reference point x Indicates position x The horizontal distance from the reference point.

2. The method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer as described in claim 1, characterized in that, If the overlying soil consists of multiple soil layers, then the weight of the overlying soil is... γ The result is obtained by weighting the thickness of each soil layer.

3. The method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer as described in claim 1, characterized in that, If there is no difference in ground elevation but there is ground load, the load is equivalent to the overburden, and the differential settlement value of the segment at the ground load location is calculated according to the segment differential settlement calculation function.

4. A computer program product, characterized in that, It includes a computer program / instruction that, when executed by a processor, implements the method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer as described in any one of claims 1 to 3.

5. A readable storage medium, characterized in that, It stores a computer program, which, when executed, implements the method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer as described in any one of claims 1 to 3.

6. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method for calculating differential settlement of shield tunnel segments under a large elevation difference overburden layer as described in any one of claims 1 to 3.

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