Optimization method for diaphragm wall and transverse force system based on single-side filling of double-hole air shaft

Abstract

The application provides a method for optimizing a diaphragm wall and a lateral force system based on one-side filling of a double-hole air shaft, comprising: a bottom plate arranged at the bottom of the double-hole air shaft; a wall body extending upward from the top of the bottom plate and fixed vertically therewith; a plurality of layers of lateral restraint mechanisms arranged at the side of the wall body to form a plurality of layers of lateral restraint to the wall body; a bottom restraint mechanism arranged at the bottom of the wall body to form vertical restraint to the wall body; a vertical or lateral cross-restraint mechanism arranged at the side of the wall body to strengthen the vertical restraint of the wall body and to form lateral cross-restraint with the plurality of layers of lateral restraint mechanisms; and a plurality of restraints formed by the plurality of restraint mechanisms to the wall body to resist the pressure of one-side filling acting on the wall body. The application disperses the filling pressure on one side of the diaphragm wall by arranging a layer plate and a rib plate on the diaphragm wall to form a multi-span lateral force two-way plate structure, and ensures the vertical bearing of the diaphragm wall to significantly optimize the stress system of the diaphragm wall under the condition of lateral load.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tunnel construction, and particularly relates to a method for optimizing a transverse stress system of a middle partition wall based on single-side soil filling of a double-hole air shaft. BACKGROUND

[0002] It is known that a working shaft needs to be arranged at the start and end points of a shield tunnel for launching and receiving of the shield. With the increase of the length of the tunnel, an air shaft also needs to be arranged in the middle of the shield tunnel to meet the ventilation of the long tunnel, and the air shaft also bears the functions of launching and receiving as an intermediate working shaft during the construction period. At present, a middle partition wall is arranged in the double-hole air shaft, which separates the air inlets and outlets and the left and right traffic lanes and reduces the transverse span of the side wall of the air shaft. The stress of the middle partition wall mainly has two parts, one part is the vertical load transmitted from the upper structure and the uniformly distributed load of each layer, and the other part is the longitudinal horizontal load transmitted to the middle partition wall from the water and soil pressure acting on the side wall outside the air shaft, and the common point is along the structure axis. Therefore, under general conditions, the middle partition wall is mainly a compression member, and the bending moment and shear force thereof are small, and the reinforcement amount thereof is small in the design, and the middle partition wall is not a key component in the design of the air shaft structure.

[0003] In particular, in order to realize the full-size test of the shield tunneling and loading in the single-side air shaft, the water and soil need to be filled on one side of the middle partition wall, and at this time, the middle partition wall becomes a key component for the safety of the whole structure. Under the condition of single-side soil filling, the middle partition wall changes from a compression member to a bending member, and the closer to the bottom of the middle partition wall, the greater the water and soil pressure, and the greater the bending moment and shear force caused thereby, so that the middle partition wall designed as a compression member cannot meet the test requirements and needs to be reinforced.

[0004] However, there is no engineering case or working condition of single-side soil filling in the double-hole air shaft in the industry, and there is also no related research or design. Under the premise of not affecting the space on the other side of the middle partition wall for the related procedures such as shield receiving and launching and ensuring the safety of the air shaft structure, how to reinforce the middle partition wall to ensure that the full-size test of the shield tunneling and loading in the single-side air shaft can be successfully completed is a problem to be solved. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a novel method for optimizing the transverse stress system of the middle partition wall under the condition of single-side soil filling of the double-hole air shaft.

[0006] According to one aspect of the present application, a middle partition wall based on single-side soil filling of a double-hole air shaft is provided, comprising:

[0007] a bottom plate arranged at the bottom of the double-hole air shaft;

[0008] a wall body extending upwardly from the top of the base plate and fixed vertically therewith;

[0009] a plurality of layers of lateral restraint mechanisms arranged at the sides of the wall body to form a plurality of layers of lateral restraint to the wall body;

[0010] a bottom restraint mechanism arranged at the bottom of the wall body to form vertical restraint to the wall body;

[0011] a vertical or lateral mid-span restraint mechanism arranged at the sides of the wall body to strengthen the vertical restraint of the wall body and to strengthen the lateral mid-span restraint formed by the plurality of layers of lateral restraint mechanisms.

[0012] a plurality of restraints formed by the plurality of layers of lateral restraint mechanisms, the bottom restraint mechanism and the vertical or lateral mid-span restraint mechanism to the wall body to resist the bending moment and shear force acting on the wall body formed by the unilateral filling.

[0013] Preferably, the side of the wall body on which the unilateral filling is defined is referred to as the filling side, and the other side is referred to as the non-filling side; the plurality of layers of lateral restraint mechanisms comprises a plurality of layers of slabs which are spaced apart vertically along the wall body and symmetrically distributed left and right within the filling side and the non-filling side.

[0014] Preferably, the bottom restraint mechanism comprises a backfill layer which is symmetrically distributed on both sides of the wall body; the height of the wall body is h1, and the height of the backfill layer is h2, which is in the range of 0.08h1≤h2≤0.12h1.

[0015] Preferably, the vertical or lateral mid-span restraint mechanism comprises:

[0016] a ribbed slab arranged at a plurality of mid-span regions of the wall body; wherein each ribbed slab is fixedly connected to the corresponding slab or / and the base plate, and the height of the ribbed slab is not greater than the width of the slab;

[0017] an anchoring member which is horizontally distributed at the bottom of the wall body and the bottom slab of the corresponding layer;

[0018] an oblique rigid support member arranged between the slab corresponding to the mid-span of the wall body and the base plate on the non-filling side;

[0019] a vertical steel support member extending upwardly and downwardly between the backfill layer on the filling side and the slab corresponding to the mid-span of the wall body;

[0020] The reinforcing plate is arranged between the top of the backfill layer and the non-filling side of the wall, and the plurality of reinforcing plates are distributed along the width direction of the wall.

[0021] According to a second aspect of the present application, a method for optimizing a lateral force system of a double-hole wind shaft single-side filling diaphragm wall is provided, the diaphragm wall comprising a bottom plate and a wall body extending upward from the bottom plate, and the optimization of the diaphragm wall comprises:

[0022] S1, adding a plurality of lateral constraints to the diaphragm wall

[0023] During the shield tunneling construction period, a plurality of layer plates are constructed on the wall body in advance, wherein the plurality of layer plates divide the wall body into an underground first layer, an underground second layer,..., and an underground Nth layer arranged in sequence from top to bottom, and when the wall body is filled with water and soil on one side, the plurality of layer plates form a plurality of lateral constraints of the diaphragm wall, and the wall body is optimized from a super-large span plate structure with three fixed constraints to a multi-span unidirectional plate structure with reduced span.

[0024] S2, increasing the constraint range of the bottom of the diaphragm wall

[0025] A backfill layer is formed by pouring backfill material on both sides of the bottom of the diaphragm wall to form vertical fixed constraints of the diaphragm wall.

[0026] S3, further strengthening the vertical or lateral mid-span constraints of the bottom of the diaphragm wall

[0027] According to the numerical calculation results, the stress range of the wall body is determined, and according to the results of the structure calculation, a plurality of vertically extending rib plates are arranged in the mid-span region of the bottom of the wall body to further divide the unidirectional plate structure into a bidirectional plate structure, wherein each rib plate is fixedly connected with the corresponding layer plate or / and the bottom plate, and the height of the rib plate is not greater than the width of the layer plate; or / and, the anchor is arranged in the mid-span of the bottom of the wall body and the bottom layer plate of the corresponding layer to further divide the unidirectional plate structure into a unidirectional plate structure with smaller span, and to constrain the deformation of the wall body and the layer plate.

[0028] Preferably, in S1, the plurality of layer plates are symmetrically arranged on the filling side and the non-filling side of the wall body.

[0029] In S2, the backfill layer is symmetrically arranged on the filling side and the non-filling side of the wall body.

[0030] In S3, the anchor is arranged in the mid-span of the bottom of the wall body and the bottom layer plate of the corresponding layer on the filling side of the wall body.

[0031] In S3, the rib plates are arranged on the non-filling side of the wall body.

[0032] Preferably, in S3, a diagonal rigid support is arranged between the floor slab and the floor slab corresponding to the non-filling side in the span of the wall.

[0033] Preferably, a vertical steel support extending upward and downward is arranged between the backfill layer on the filling side of the wall and the floor slab corresponding to the span of the wall.

[0034] Preferably, a plurality of reinforcing rib plates are welded between the top of the backfill layer and the non-filling side of the wall, and the plurality of reinforcing rib plates are distributed along the width direction of the wall.

[0035] Preferably, N=5, wherein the floor slab corresponding to the bottom of the third underground layer in the span of the wall, the upper part of the rib plate is welded to the bottom surface of the floor slab at the bottom of the third underground layer, and the lower part is welded to the floor slab.

[0036] Compared with the prior art, the above technical solutions have at least the following advantages:

[0037] The method for optimizing the diaphragm wall and transverse stress system based on single-side filling of the double-hole air shaft in the embodiment of the application can disperse the filling pressure on one side of the diaphragm wall, reduce the bending moment and shear force generated by the filling load on the diaphragm wall, especially in the lower region of the diaphragm wall, thereby significantly optimizing the stress system of the diaphragm wall under the transverse load condition on the premise of ensuring the vertical bearing capacity of the diaphragm wall, effectively reducing the deformation of the diaphragm wall, ensuring the reliability of the diaphragm wall, and the operation method is simple and can be directly applied to actual construction.

[0038] The method for optimizing the diaphragm wall and transverse stress system based on single-side filling of the double-hole air shaft in the embodiment of the application divides the wall into multiple layers, facilitates the calculation of the stress of the wall by the staff, and marks according to different stress conditions, so that the construction personnel can intuitively know the region of the diaphragm wall that needs to be reinforced.

[0039] The method for optimizing the diaphragm wall and transverse stress system based on single-side filling of the double-hole air shaft in the embodiment of the application uses common materials for optimizing the transverse stress of the diaphragm wall, has a simple structure, is convenient for construction, and has low cost. BRIEF DESCRIPTION OF DRAWINGS

[0040] Other features, objects, and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the following drawings:

[0041] Figure 1 FIG. 1 is a structural schematic diagram of a double-hole air shaft and a diaphragm wall in an embodiment of the application (without structural optimization);

[0042] Figure 2 Structure diagram of the optimized partition wall of the lateral force system of a preferred embodiment of the present application;

[0043] Figure 3 The left view schematic diagram of Figure 2 ;

[0044] Wherein: A, air shaft; t, passage; B, partition wall; 1, bottom plate; c1, backfill layer; 2, wall body; 3, layer plate; m, reinforcing rib plate; n, vertical steel support; 4, rib plate;

[0045] Figure 4 Flow chart of the optimization method of the partition wall of the lateral force system based on the single-side filling of the double-hole air shaft in another preferred embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many different ways other than those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0047] In the description of the present application, it should be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0048] In addition, the terms “first” and “second” are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with “first” and “second” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “a plurality of” is at least two, such as two, three, etc., unless otherwise specifically limited.

[0049] In the present application, unless specifically defined otherwise, the terms "mounting", "connected", "connecting", "fixed", and "fixing" should be construed as broad terms, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection; can be direct connection, can also be indirect connection through intermediate medium, can be internal communication of two elements or interaction relationship of two elements, unless specifically defined otherwise. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] In the present application, unless specifically defined otherwise, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0051] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0052] Reference is made to Figures 1-3The application provides a single-side filling based partition wall of a double-hole air shaft. The wall is defined as a filling side and a non-filling side. The partition wall comprises a bottom plate 1, a wall body 2, a plurality of horizontal constraint mechanisms, a bottom constraint mechanism and a vertical or horizontal mid-span constraint mechanism. The bottom plate 1 is arranged at the bottom of the double-hole air shaft. The wall body 2 extends upward from the top of the bottom plate 1 and is fixed vertically. The plurality of horizontal constraint mechanisms are arranged at the side of the wall body to form a plurality of horizontal constraints on the wall body. The bottom constraint mechanism is arranged at the bottom of the wall body to form a vertical constraint on the wall body. The vertical or horizontal mid-span constraint mechanism is arranged at the side of the wall body to strengthen the vertical constraint on the wall body and the horizontal mid-span constraint formed by the plurality of horizontal constraint mechanisms. The plurality of constraints formed by the plurality of horizontal constraint mechanisms, the bottom constraint mechanism and the vertical or horizontal mid-span constraint mechanism on the wall body resist the bending moment and shear force formed by the single-side filling on the wall body. The structure of the embodiment is decomposed from the original large-span structure into a small-span structure. The horizontal load generated by the filling is transmitted to the side wall and the bottom plate which have large bearing capacity through the layer plate and the rib plate. The transmitted force is opposite to the direction of the water and soil load outside the side wall and under the bottom plate, which is a favorable load.

[0053] In a preferred embodiment of the application, the plurality of horizontal constraint mechanisms comprises a plurality of layer plates 3 which are arranged symmetrically along the wall body 2 in the filling side and the non-filling side.

[0054] In a preferred embodiment of the application, the bottom constraint mechanism comprises a backfill layer c1 which is arranged symmetrically on both sides of the wall body 2. The height of the wall body 2 is h1 and the height of the backfill layer c1 is h2, and the range is 0.08h1≤h2≤0.12h1.

[0055] In a preferred embodiment of the application, the vertical or horizontal mid-span constraint mechanism comprises a rib plate 4, an anchor, an inclined rigid support, a vertical steel support n and a reinforcing rib plate m. A plurality of rib plates 4 are arranged in the mid-span area of the wall body. Each rib plate is fixedly connected with the corresponding layer plate and / or bottom plate. In order not to interfere with the operation during the construction period of the air shaft, the height of the rib plate is not greater than the width of the layer plate. The anchor is horizontally distributed in the mid-span area of the wall body and the bottom layer plate of the corresponding layer. The inclined rigid support is arranged between the layer plate and the bottom plate corresponding to the mid-span area of the wall body on the non-filling side. The vertical steel support is arranged between the backfill layer on the filling side and the layer plate corresponding to the mid-span area of the wall body and extends upward and downward. The reinforcing rib plate is arranged between the top of the backfill layer and the non-filling side of the wall body. A plurality of reinforcing rib plates are arranged symmetrically along the width direction of the wall body.

[0056] The above embodiment can disperse the earth pressure on the side of the partition wall by arranging the slab and the rib plate on the partition wall, thereby optimizing the stress system of the partition wall under the transverse load condition on the premise of ensuring the vertical bearing capacity of the partition wall, and effectively reducing the deformation of the partition wall to ensure the reliability of the partition wall.

[0057] In one specific example of the present application, as shown in Figures 1 to 3 The double-hole wind shaft structure of the present embodiment is a conventional wind shaft A, and two shield tunnels t pass through the wind shaft A.

[0058] The partition wall B of the present embodiment is arranged between the two shield tunnels t, and includes a bottom plate 1 and a wall body 2. The bottom plate 1 is arched downward, and the wall body 2 extends vertically upward from the bottom plate 1, wherein the height of the wall body 2 is h1=38200mm, and the thickness is d1=1200mm.

[0059] Referring to Figure 2 The right side of the wall body 2 is the side close to the earth, and the left side is the side away from the earth. When filling the earth and water on the right side of the wall body 2, the height of the earth is 25900mm, and the maximum water level is 25900mm. In particular, after the tunnel passes through the wind shaft and the excavation is completed, the earth filling height in the wind shaft is increased by 5000mm, and the water level is lowered by more than 2500mm, so as to ensure that the horizontal load of the loading condition on the partition wall is not higher than that of the excavation condition.

[0060] Referring to Figure 4 Based on the same inventive concept, in other embodiments of the present application, a partition wall transverse stress system optimization method based on double-hole wind shaft single-side earth filling is provided, including the following steps:

[0061] S1, adding multiple layers of transverse constraints to the partition wall;

[0062] S2, increasing the constraint range of the bottom of the partition wall;

[0063] S3, further strengthening the vertical or transverse mid-span constraint at the bottom of the partition wall.

[0064] In S1, the multi-layered layer plates 3 are welded on the wall body 2 in an up-down interval and horizontal extension, wherein the multi-layered layer plates 3 divide the wall body into the underground first layer, the underground second layer, …, and the underground Nth layer in a top-down sequence, and when the soil is filled on one side of the wall body 2, the multi-layered layer plates 3 form the multi-layered lateral constraint of the wall body 2, that is, the layer plates greatly increase the lateral stiffness and are fixed with the side wall and can be regarded as effective constraint. In the embodiment, N=5, that is, the layer plates 3 are four and divide the wall body 2 into the underground first layer, the underground second layer, the underground third layer, the underground fourth layer, and the underground fifth layer in a bottom-up sequence, wherein according to the stress test analysis of the wall body 2 under the filling of the soil on one side, the height ratio of the underground first layer, the underground second layer, the underground third layer, the underground fourth layer, and the underground fifth layer is 0.75:0.84:0.61:0.87:1, and the mid-span position of the wall body 2 corresponds to the layer plate 3 at the bottom of the underground third layer. In this way, the wall body is divided into multiple layers, which facilitates the staff to use the finite element method to calculate the stress of the wall body and to mark according to different stress conditions, and the construction personnel can intuitively know the area needing to be reinforced on the partition wall.

[0065] In the embodiment, the heights of the underground first layer, the underground second layer, the underground third layer, the underground fourth layer, and the underground fifth layer are 6300 mm, 7050 mm, 5100 mm, 7300 mm, and 8350 mm in sequence.

[0066] Specifically, four layer plates 3 are welded on the left and right sides of the wall body 2, and the four layer plates 3 on the two sides are arranged in one-to-one alignment, and the layer plates 3 on each side are arranged in up-down alignment.

[0067] In S2, the backfill material is poured at the bottom of the wall body 2 to form the backfill layer c1, so as to form the vertical fixed constraint of the wall body 2.

[0068] Specifically, the backfill material is plain concrete and is poured upwards from the top surface of the bottom plate 1, and the backfill height is h2, wherein 0.08h1≤h2≤0.12h1. In the embodiment, h2=3500 mm.

[0069] In order to improve the stability of the bottom of the partition wall, when the plain concrete is poured, the pouring is simultaneously performed along the left and right sides of the wall body 2, so as to ensure that the heights of the backfill layers c1 on the left and right sides of the wall body 2 are consistent.

[0070] In addition, the vertical steel support n extending upwards and downwards is arranged between the backfill layer c1 on the side close to the soil of the wall body 2 and the layer plate 3 corresponding to the mid-span position of the wall body 2. In the embodiment, the vertical steel support is a profile steel with the upper end and the lower end welded with the backfill layer c1 and the corresponding layer plate 3, respectively.

[0071] Further, a plurality of reinforcing rib plates m are welded between the left side of the wall 2 and the top of the backfill layer c1 and are spaced along the width direction of the wall 2.

[0072] In S3, the range of the wall 2 with greater stress is determined according to the numerical calculation result, and a plurality of vertically extending rib plates are arranged in the midspan region of the bottom several layers of the wall 2 according to the result of the structural calculation to further divide the single-way slab structure into a two-way slab structure, wherein each rib plate 4 is fixedly connected with the corresponding floor slab 3 or / and the bottom slab 1, and the height of the rib plate 4 is not greater than the width of the floor slab 3. The anchor tension (see Figure 2 the right side of the backfill side for simplicity) is distributed transversely in the bottom of the corresponding floor slab 3 in the midspan of the bottom several layers of the wall 2 to further divide the single-way slab structure into a single-way slab structure with smaller span and constrain the deformation of the wall and the floor slab.

[0073] Specifically, the rib plate 4 is welded on the side of the wall 2 away from the backfill (the left side), and the upper part of the rib plate 4 is welded on the bottom surface of the floor slab 3 at the bottom of the third underground layer, and the lower part is welded on the bottom slab 1. In some embodiments, a plurality of rib plates 4 can be arranged and spaced along the length direction of the wall 2.

[0074] Specifically, the anchor tension (not shown in the figure, but not difficult to imagine) is arranged in the midspan of the wall 2 and the corresponding floor slab 3 (the floor slab 3 at the bottom of the third underground layer) on the side of the wall 2 close to the backfill. The anchor tension is a conventional construction means, which will not be described here.

[0075] Meanwhile, an inclined rigid support (see Figure 2 the left side of the non-backfill side for simplicity) can also be arranged in the midspan of the wall 2 and the corresponding floor slab 3 on the side of the wall 2 away from the backfill. The inclined rigid support here can be various common rigid supports, such as a steel support, which extends obliquely upward and downward, and the upper end of the steel support is welded on the corresponding floor slab 3 and the lower end is welded on the bottom slab 1.

[0076] The midspan region mentioned in the above embodiments refers to the middle region of the space surrounded by the constraint members, and the floor slab divides the partition wall into a plurality of spaces in the vertical direction. The middle region of each space is regarded as the midspan, and the midspan region of the bottom several layers specifically refers to the midspan region of the several layers extending upward from the bottom (the specific number of layers is several, which is determined according to the size of the midspan bending moment)

[0077] The above detailed description of the present application is intended to enable a person skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application should be covered within the protection scope of the present application.

[0078] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The above preferred features can be combined in any manner without conflict, and used.

Claims

1. A central partition wall based on single-sided backfill of a double-cavity ventilation shaft, characterized in that, include: A base plate, wherein the base plate is disposed at the bottom of the dual-hole ventilation shaft; A wall extending from the top of the base plate upwards and fixed perpendicularly thereto; A multi-layer lateral constraint mechanism is provided on the side of the wall to form a multi-layer lateral constraint on the wall; A bottom constraint mechanism is provided at the bottom of the wall to form a vertical constraint on the wall; A vertical or horizontal mid-span constraint mechanism is provided on the side of the wall to strengthen the vertical constraint of the wall and strengthen the horizontal mid-span constraint formed by the multi-layer horizontal constraint mechanism. Based on the multiple constraints formed on the wall by the multi-layered lateral constraint mechanism, bottom constraint mechanism and vertical or lateral mid-span constraint mechanism, the pressure exerted on the wall by the unilateral backfill soil is resisted. The bottom restraint mechanism includes a backfill layer, which is symmetrically distributed on both sides of the wall; the height of the wall is h1, and the height of the backfill layer is h2, with a range of 0.08h1≤h2≤0.12h1.

2. A central partition wall based on single-sided backfill of a double-tunnel ventilation shaft according to claim 1, characterized in that, The side of the wall where soil is filled on one side is called the filled side, and the other side is called the non-filled side; the multi-layer lateral restraint mechanism includes multi-layer plates, which are spaced vertically and symmetrically distributed horizontally along the wall on the filled side and the non-filled side.

3. A central partition wall based on single-sided backfill of a double-tunnel ventilation shaft according to claim 2, characterized in that, The vertical or lateral mid-span constraint mechanism includes: Ribs, a plurality of ribs are disposed in the mid-span area of ​​several layers at the bottom of the wall; wherein each rib is fixedly connected to the corresponding layer plate and / or the bottom plate, and the height of the rib is not greater than the width of the layer plate; Anchors are provided, which are laterally distributed with the bottom slab of the corresponding layer at several mid-spans of the bottom of the wall. An inclined rigid support member is disposed between the layer slab and the bottom slab on the non-fill side of the span of the wall. A vertical steel support member extends vertically between the backfill layer located on the backfill side and the corresponding layer slab in the middle of the wall span; A reinforcing rib is provided between the top of the backfill layer and the non-fill side of the wall, and the plurality of reinforcing ribs are distributed at intervals along the width direction of the wall.

4. A method for optimizing the transverse stress system of a central partition wall based on single-sided backfill of a double-tunnel ventilation shaft, characterized in that, The central partition wall includes a base plate and a wall extending upward from the base plate. Optimizing the central partition wall includes: S1. Add multiple layers of lateral constraints to the central partition wall. During the tunnel boring machine (TBM) construction phase, multiple layers of slabs with vertical spacing are pre-constructed on the wall. These multiple layers of slabs divide the wall into underground layers 1, 2, ... N, distributed from top to bottom. When one side of the wall is filled with soil and water, the multiple layers of slabs form multiple lateral constraints of the central partition wall. The wall structure is optimized from a super-large span slab structure with fixed constraints on three sides to a multi-span unidirectional slab structure with a reduced span. S2. Increase the constraint range at the bottom of the central partition wall. After pouring backfill material on both sides of the bottom of the partition wall, a backfill layer is formed to create a vertical fixed constraint for the partition wall. S3. Further strengthen the vertical or horizontal mid-span restraint at the bottom of several layers of the central partition wall where the stress is greater. The stress range of the wall is determined based on the numerical calculation results. Based on the structural verification results, several vertically extending ribs are set in the mid-span area of ​​several layers at the bottom of the wall to further divide the one-way slab structure into a two-way slab structure. Each rib is fixedly connected to the corresponding layer slab and / or the bottom slab, and the height of the rib is not greater than the width of the layer slab. Or / and, horizontally distributed anchors are set in the mid-span area of ​​several layers at the bottom of the wall to further divide the one-way slab structure into one-way slab structures with smaller spans, thereby constraining the deformation of the wall and the layer slab.

5. The method for optimizing the transverse stress system of the central partition wall based on single-sided backfill of a double-tunnel ventilation shaft according to claim 4, characterized in that, In S1, the multi-layered panels are symmetrically arranged on the soil-filled side and the non-soil-filled side of the wall; In S2, the backfill layer is symmetrically arranged on the soil-filled side and the non-soil-filled side of the wall; In S3, anchoring is performed on the bottom layer slab of the corresponding layer located on the backfill side of the wall at several mid-spans at the bottom of the wall. In S3, all the ribs are located on the non-fill side of the wall.

6. The method for optimizing the transverse stress system of the central partition wall based on single-sided backfill of a double-tunnel ventilation shaft according to claim 4, characterized in that, In S3, an oblique rigid support is provided between the slab and the base plate on the non-fill side corresponding to the span of the wall.

7. The method for optimizing the transverse stress system of a central partition wall based on single-sided backfill of a double-tunnel ventilation shaft according to claim 6, characterized in that: Vertical steel supports extending vertically are provided between the backfill layer located on the earth-fill side of the wall and the corresponding slab in the middle of the wall span.

8. The method for optimizing the transverse stress system of a central partition wall based on single-sided backfill of a double-tunnel ventilation shaft according to claim 7, characterized in that, A plurality of reinforcing ribs are welded between the top of the backfill layer and the non-fill side of the wall, wherein the plurality of reinforcing ribs are spaced apart along the width direction of the wall.

9. The method for optimizing the transverse stress system of a central partition wall based on single-sided backfill of a double-tunnel ventilation shaft according to claim 4, characterized in that, The N=5, wherein the mid-span of the wall corresponds to the floor slab located at the bottom of the third underground level, and the upper part of the rib plate is welded to the bottom surface of the floor slab located at the bottom of the third underground level, and the lower part is welded to the base plate.

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