Method for determining pressure of covering soil on shield tunneling tunnel

Abstract

The invention provides a method for determining the soil covering pressure on a shield tunneling tunnel, and relates to the technical field of soil covering pressure determination, and the method comprises the steps: obtaining a calculation theoretical model corresponding to the soil covering on the shield tunneling tunnel; according to the calculation theoretical model, determining a shear expansion exerting coefficient # imgabs0 # under different stress levels; according to the # imgabs 1 #, determining an included angle # imgabs 2 # between a tunnel excavation shear zone corresponding to the dilatancy angle under different stress levels and the horizontal direction; according to # imgabs3 #, determining a calculation formula of the soil arch height related to the soil covering pressure on the tunnel and a calculation formula of the soil arch height related to the stratum loss rate; according to the calculation formula of the earth pressure on the tunnel about the soil arch height and the calculation formula of the soil arch height about the stratum loss rate, the calculation formula of the earth pressure on the tunnel about the stratum loss rate is determined, and then the earth pressure on the shield tunneling tunnel is determined. And the soil covering pressure on the shield tunneling tunnel can be accurately determined.

Description

Technical Field

[0001] The invention relates to the technical field of determining overburden pressure, and in particular to a method for determining overburden pressure on a shield tunnel. Background Art

[0002] With the increasingly accelerated urbanization process, underground space development has become an important means to increase urban available space and alleviate traffic pressure. As a method of underground space construction, shield method has been widely used in transportation, electricity, water conservancy and other fields. Shield tunneling will cause soil arching effect inside the stratum, resulting in significant changes in the overburden pressure on the tunnel; therefore, it is a prerequisite for accurately predicting the overburden pressure on tunnel excavation to reasonably evaluate the evolution process of the soil arching effect of shield tunneling and propose a soil arching effect theory based on this; at present, although a large number of tunnel excavation soil arching effect theories have been proposed in the existing technology based on model tests and numerical simulation results, combined with soil limit equilibrium analysis, the relevant theories still have many limitations, and the determination of the overburden pressure on the shield tunnel is still not accurate enough, resulting in inaccurate setting of relevant parameters during shield tunneling. Therefore, how to accurately determine the overburden pressure on the shield tunnel has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the above technical problems, the technical solution adopted by the present invention is: According to a first aspect of the present application, a method for determining the overburden pressure of a shield tunnel is provided, the method comprising the following steps: S100, obtaining a calculation theoretical model corresponding to the overburden on the shield tunnel; S200, determining the shear expansion coefficient under different stress levels according to the calculation theoretical model ; S300, according to , determine the angle between the tunnel excavation shear zone and the horizontal direction corresponding to the shear dilation angle under different stress levels ; S400, according to , determine the calculation formula of the overburden pressure on the tunnel in relation to the soil arch height and the calculation formula of the soil arch height in relation to the stratum loss rate; S500, determining a calculation formula for the overburden pressure on the tunnel in relation to the soil arch height and a calculation formula for the soil arch height in relation to the stratum loss rate, and further determining the overburden pressure on the shield tunnel.

[0004] According to another aspect of the present application, a non-transitory computer-readable storage medium is also provided, in which at least one instruction or at least one program is stored, and the at least one instruction or at least one program is loaded and executed by a processor to implement the above-mentioned method for determining the overburden pressure on a shield tunnel.

[0005] According to another aspect of the present application, an electronic device is provided, including a processor and the above-mentioned non-transitory computer-readable storage medium.

[0006] The present invention has at least the following beneficial effects: The method for determining the overburden pressure on a shield tunnel of the present invention obtains a calculation theoretical model corresponding to the overburden pressure on the shield tunnel; and determines the shear expansion coefficient under different stress levels according to the calculation theoretical model. f y ;according to f y , determine the angle between the tunnel excavation shear zone and the horizontal direction corresponding to the shear dilation angle under different stress levels a s ;according to a s , determine the calculation formula of the overburden pressure on the tunnel in relation to the soil arch height and the calculation formula of the soil arch height in relation to the stratum loss rate; according to the calculation formula of the overburden pressure on the tunnel in relation to the soil arch height and the calculation formula of the soil arch height in relation to the stratum loss rate, determine the calculation formula of the overburden pressure on the tunnel in relation to the stratum loss rate, and then determine the overburden pressure on the shield tunnel. The method of the present invention comprehensively considers various factors and can accurately determine the overburden pressure on the shield tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0008] Figure 1 A flow chart of a method for determining overburden pressure on a shield tunnel provided by an embodiment of the present invention; Figure 2 A schematic diagram of specific implementation steps provided for an embodiment of the present invention; Figure 3 A schematic diagram of a calculation theory model provided by an embodiment of the present invention; Figure 4 A schematic diagram of stress analysis provided by an embodiment of the present invention; Figure 5 A schematic diagram of the soil Mohr circle inside the shear plane provided by an embodiment of the present invention; Figure 6 A schematic diagram of the Mohr circle of soil at the shear plane provided by an embodiment of the present invention; Figure 7 A schematic diagram of a unit body force analysis provided by an embodiment of the present invention; Figure 8 A schematic diagram of a shear band provided by an embodiment of the present invention; Fig. 9 A schematic diagram comparing theoretical results and experimental results provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0009] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0010] It should be noted that, based on the present disclosure, those skilled in the art should understand that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement a device and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0011] The following will refer to Figure 1 The flowchart of the method for determining the overburden pressure on a shield tunnel is shown, and a method for determining the overburden pressure on a shield tunnel is introduced.

[0012] See also Figure 2 When the method for determining the overburden pressure on a shield tunnel is implemented, the following steps may be included: S100, obtaining a calculation theoretical model corresponding to the overburden on the shield tunnel.

[0013] Reference Figure 3 , which is a theoretical model for calculating the overburden pressure on the tunnel. The model is mainly composed of an inverted trapezoid (or rectangle) on the upper part and a classified triangle on the lower part. The starting position of the shear surface on both sides of the soil arch calculation width is located at the intersection of the ±45° radius based on the tunnel centerline and the circumference.

[0014] When the stress level is small, the shear surface develops vertically upward; when the stress level is large and the soil dilatancy is weak, the shear surface develops inclined to both sides; the calculated height of the soil arch is h sa , when buried deep C Greater than the calculated height of soil arch h sa When calculating the soil arch height, the strata above it are considered to be unaffected by tunnel excavation.

[0015] The calculated height of the soil arch increases with the increase of the ground loss rate. When the tunnel is shallow, the soil arch may develop rapidly to the surface as the ground loss rate increases; when the tunnel is deep, the height of the soil arch may not reach the surface. The calculated width of the soil arch at the top of the tunnel is 2 B , the calculated width of the soil arch at each position in the upper part is .

[0016] The model assumes the following: (1) The soil arch type above the tunnel excavation is a circular arc-shaped large principal stress arch; (2) The soil inside the soil arch area is in the limit state and meets the Mohr-Coulomb failure criterion; (3) The stratum loss caused by shield tunneling is filled by the volume change caused by the shear expansion of the soil in the upper shear zone.

[0017] S200, determining the shear expansion coefficient under different stress levels according to the calculation theoretical model .

[0018] The shear expansion coefficient under different stress levels Determined according to the following formula: ; In the formula, is the mean effective stress p ' is the peak dilatancy angle of soil at 150 kPa; is the mean effective stress p 'The maximum dilatancy angle of soil when the pressure is greater than 150kPa.

[0019] S300, according to , determine the angle between the tunnel excavation shear zone and the horizontal direction corresponding to the shear dilation angle under different stress levels ; can be determined by linear interpolation as follows: ; in, is the internal friction angle of soil.

[0020] The third step is to determine the calculation formula for the overburden pressure on the tunnel in relation to the soil arch height.

[0021] Reference Figure 3 , is the angle between the major principal stress direction of the soil at the shear plane and the vertical direction, ,and is the angle between the direction of the major principal stress of the soil at the shear plane and the shear plane; is the angle between the direction of the major principal stress at a point on the major principal stress trace and the vertical direction, . is the normal stress perpendicular to the shear plane, is the shear stress parallel to the shear plane, is the radius of the principal stress trace of the circular soil arch.

[0022] The relevant parameters are calculated as follows: ; ; ; ; Among them, D is the tunnel diameter, C is the tunnel depth, and z is the vertical coordinate.

[0023] Reference Figure 4 and Figure 5 , the relationship between the major and minor principal stresses and the vertical and horizontal principal stresses of the soil at any position in the shear plane during shield tunneling can be obtained: ; ; Combining the above two equations, the lateral earth pressure coefficient can be obtained as: ; In the formula, , is the passive earth pressure coefficient; σ 1 is the major principal stress, σ 3 is the minor principal stress, σ v is the vertical earth pressure, σ h is the horizontal earth pressure.

[0024] On the tunnel centerline , lateral earth pressure coefficient K o = K p On the shear plane , lateral earth pressure coefficient K s The calculation formula is as follows: ; Reference Figure 6 , the normal stress at the shear surface can be obtained , shear stress Relationship with major and minor principal stresses: ; ; ; It is the angle between the direction of the largest principal stress in the soil at the shear plane and the shear plane.

[0025] Reference Figure 7, and perform unit body force analysis, we can get: ; ; Determine the lateral earth pressure coefficient K av : ; Determine the normal stress at the shear plane: ; ; Determine the shear stress at the shear plane: ; is the shear stress parallel to the shear plane, is the average vertical earth pressure.

[0026] Determine the differential equation: ; in, It is the weight of soil.

[0027] Solving the above formula, we can get , will be written as The first-order nonhomogeneous linear differential equation form of is: ; Solving the above formula, we can get: ; In the formula, C 1 is a constant to be determined.

[0028] Substitute the boundary conditions: when z = C - h sa hour, .

[0029] We can get: ; The above calculation conditions must be met C - h sa ≤ z ≤ C .

[0030] Overburden pressure on tunnel The calculation formula is: ; When the mean effective stress pWhen '<150kPa, the stress level has almost no effect on the shear dilatancy of the soil. , the above formula cannot be solved directly, but it can be approximated by finding the limit.

[0031] The overburden pressure on the tunnel can be obtained by solving s av2 The calculation formula is: ; S400, according to , determine the calculation formula for the overburden pressure on the tunnel in relation to the soil arch height and the calculation formula for the soil arch height in relation to the stratum loss rate.

[0032] Reference Figure 8 , the simplified shear band volume is ( V 1+ V 2): ; ; in, V 1 is the volume of the shear zone above the tunnel top plane, V 2 is the volume of the shear zone below the tunnel top plane.

[0033] In this embodiment, the critical void ratio To calculate the volume change of the shear band, the change in porosity is ,in, e 0 is the initial porosity. The volume change caused by the shear expansion of the soil inside the shear zone is According to the above assumption 3, it can be known that it is equal to the volume lost by excavation, and the following formula can be obtained: ; The calculation formula of soil arch height and stratum loss rate is obtained by calculating the above formula: ; In the formula, ; S500, determining a calculation formula for the overburden pressure on the tunnel in relation to the soil arch height and a calculation formula for the soil arch height in relation to the stratum loss rate, and further determining the overburden pressure on the shield tunnel.

[0034] Substitute the above two equations into the above tunnel overburden pressure and The calculation formula can be used to obtain the overburden pressure of deep / shallow shield tunnel excavation.

[0035] In the above two formulas, for the displacement mode of the model tunnel in the model test that uniformly shrinks toward the center of the tunnel, it will cause a large rebound deformation of the stratum at the bottom of the tunnel. It can be considered that half of the stratum loss caused by tunnel excavation is filled by the shear expansion of the upper shear band. That is, it is necessary to multiply the coefficient of 0.5 on the left side of the formula. For actual engineering, the above formula can be used directly for calculation.

[0036] In the prior art, the variation law of the overburden pressure on the tunnel with the increase of the stratum loss rate was obtained through the centrifugal model test of tunnel excavation. The diameter of the prototype tunnel was 3.2m and the soil weight was 14.61kN / m 3 , the internal friction angle of the soil is 32°, the initial void ratio is 0.814, and the burial depth ratio is 6.3. In order to verify the accuracy of the above theoretical calculation method, the above theory is used to calculate the test conditions in the prior art.

[0037] Reference Fig. 9 , which is a comparison chart between the theoretical calculation results, the experimental results and the theory in the prior art. Fig. 9 It can be seen that the theoretical calculation results are in good agreement with the measured results, indicating that the theoretical model can accurately predict the overburden pressure on the tunnel under different stratum losses.

[0038] The method for determining the overburden pressure on a shield tunnel in this embodiment obtains a calculation theoretical model corresponding to the overburden on a shield tunnel; and determines the shear expansion coefficient under different stress levels according to the calculation theoretical model. f y ;according to f y , determine the angle between the tunnel excavation shear zone and the horizontal direction corresponding to the shear dilation angle under different stress levels a s ;according to a s , determine the calculation formula of the overburden pressure on the tunnel in relation to the soil arch height and the calculation formula of the soil arch height in relation to the stratum loss rate; according to the calculation formula of the overburden pressure on the tunnel in relation to the soil arch height and the calculation formula of the soil arch height in relation to the stratum loss rate, determine the calculation formula of the overburden pressure on the tunnel in relation to the stratum loss rate, and then determine the overburden pressure on the shield tunnel. The method of the present invention comprehensively considers various factors and can accurately determine the overburden pressure on the shield tunnel.

[0039] In addition, although the steps of the method in the present disclosure are described in a specific order in the drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc.

[0040] An embodiment of the present invention also provides a non-transitory computer-readable storage medium, which can be set in an electronic device to store at least one instruction or at least one program related to implementing a method in a method embodiment. The at least one instruction or the at least one program is loaded and executed by the processor to implement the method provided in the above embodiment.

[0041] The program product may adopt any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0042] Computer readable signal media may include data signals propagated in baseband or as part of a carrier wave, in which readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Readable signal media may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0043] The program code embodied on the readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the foregoing.

[0044] Program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0045] An embodiment of the present invention further provides an electronic device, comprising a processor and the aforementioned non-transitory computer-readable storage medium.

[0046] The electronic device is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0047] The electronic device is presented in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: the at least one processor mentioned above, the at least one memory mentioned above, and a bus connecting different system components (including the memory and the processor).

[0048] The memory stores program codes, which can be executed by the processor, so that the processor executes the steps in various embodiments described in this specification.

[0049] The memory may include readable media in the form of volatile memory, such as random access memory (RAM) and / or cache memory, and may further include read only memory (ROM).

[0050] The memory may also include a program / utility having a set (at least one) of program modules, such program modules including but not limited to: an operating system, one or more application programs, other program modules and program data, each of which or some combination may include an implementation of a network environment.

[0051] The bus may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus architectures.

[0052] The electronic device may also communicate with one or more external devices (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may communicate with one or more devices that enable a user to interact with the electronic device, and / or may communicate with any device (e.g., routers, modems, etc.) that enables the electronic device to communicate with one or more other computing devices. Such communication may be performed through an input / output (I / O) interface. Furthermore, the electronic device may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) through a network adapter. The network adapter communicates with other modules of the electronic device through a bus. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0053] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the implementation of the present disclosure.

[0054] An embodiment of the present invention further provides a computer program product, which includes program code. When the program product is run on an electronic device, the program code is used to enable the electronic device to execute the steps of the method according to various exemplary embodiments of the present invention described above in this specification.

[0055] Although some specific embodiments of the present invention have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present invention. It should also be understood by those skilled in the art that various modifications may be made to the embodiments without departing from the scope and spirit of the present invention.

Claims

1. A method for determining the overburden pressure of a shield tunnel, characterized in that: The method comprises the following steps: S100, obtaining a calculation theoretical model corresponding to the overburden on the shield tunnel; S200, determining the shear expansion coefficient under different stress levels according to the calculation theoretical model ; S300, according to , determine the angle between the tunnel excavation shear zone and the horizontal direction corresponding to the shear dilation angle under different stress levels ; S400, according to , determine the calculation formula of the overburden pressure on the tunnel in relation to the soil arch height and the calculation formula of the soil arch height in relation to the stratum loss rate; S500, determining a calculation formula for the overburden pressure on the tunnel in relation to the soil arch height and a calculation formula for the soil arch height in relation to the stratum loss rate, and further determining the overburden pressure on the shield tunnel.

2. The method for determining the overburden pressure of a shield tunnel according to claim 1, characterized in that: The calculation theoretical model includes: an inverted trapezoid or rectangle on the upper part and a classified triangle on the lower part; the starting position of the shear surface on both sides of the soil arch calculation width is located at the intersection of the ±45° radius and the circumference based on the tunnel centerline; the soil arch calculation height is h sa , when the burial depth C is greater than the calculated height of the soil arch h sa When the soil arch is calculated, the strata above the soil arch calculation height are not affected by tunnel excavation; the soil arch calculation width at the tunnel top is 2 B , the calculated width of the soil arch at each position in the upper part is 2 B z ; .

3. The method for determining the overburden pressure of a shield tunnel according to claim 2, characterized in that: It complies with the following formula: ； in, is the mean effective stress; p ' is the peak dilatancy angle of soil at 150 kPa; is the mean effective stress p 'The maximum dilatancy angle of soil when the pressure is greater than 150kPa.

4. The method for determining the overburden pressure of a shield tunnel according to claim 3, characterized in that: It complies with the following formula: ； in, is the internal friction angle of soil.

5. The method for determining the overburden pressure of a shield tunnel according to claim 4, characterized in that: B and B z It complies with the following formula: ； ； Among them, D is the tunnel diameter, C is the tunnel depth, and z is the vertical coordinate.

6. The method for determining the overburden pressure of a shield tunnel according to claim 5, characterized in that: The relationship between the major and minor principal stresses and the vertical and horizontal principal stresses of the soil at any position in the shear plane during shield tunneling: ； ； in, is the angle between the direction of the major principal stress at a point on the major principal stress trace and the vertical direction; , is the major principal stress, is the minor principal stress, is the vertical earth pressure, is the horizontal earth pressure; according to and , determine the lateral earth pressure coefficient K, where K conforms to the following formula: ； In the formula, K p is the passive earth pressure coefficient, ; On the tunnel centerline, , lateral earth pressure coefficient K o = K p On the shear plane, , is the angle between the major principal stress direction of the soil at the shear plane and the vertical direction, ; Lateral earth pressure coefficient K s The calculation formula is as follows: ； Get the normal stress at the shear surface , shear stress Relationship with major and minor principal stresses: ； ； ； in, is the angle between the direction of the major principal stress of the soil at the shear plane and the shear plane; and then we get: ； ； in, is the shear stress parallel to the shear plane, is the average vertical earth pressure; Determine the lateral earth pressure coefficient K av : ； Determine the normal stress at the shear plane: ； in K n is the ratio of the normal stress at the shear plane to the average vertical earth pressure; ； Determine the shear stress at the shear plane: ； Determine the differential equation: ； in, It is the weight of soil; Solve the above formula and set the default assignment parameter , will be written as The first-order nonhomogeneous linear differential equation form of is: ； Solving the above formula, we can get: ； In the formula, C 1 is a constant to be determined; Substitute the boundary conditions: when z = C - h sa hour, ; We can get: ； The above calculation conditions must be met C - h sa ≤ z ≤ C ; Overburden pressure on tunnel The calculation formula is: ； The overburden pressure on the tunnel can be obtained by solving The calculation formula is: 。 7. The method for determining the overburden pressure of a shield tunnel according to claim 6, characterized in that: Step S500 includes: The simplified shear band volume is V 1+ V 2, among which, V 1 is the volume of the shear zone above the tunnel top plane, V 2 is the volume of the shear zone below the tunnel top plane; where, ； ； Critical porosity ratio To calculate the volume change of the shear band, the change in porosity is ,in, e 0 is the initial porosity; the volume change caused by the shear expansion of the soil inside the shear zone is ;get: ； in, is the stratum loss rate, and the calculation formula of soil arch height and stratum loss rate is further obtained: ； in, ; Combination and The calculation formula is used to obtain the overburden pressure on the tunnel excavation.

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