Shield tunnel bed void state identification method

Abstract

The application discloses a kind of shield tunnel bed void state identification methods, comprising the following steps: step one, establish the numerical model of shield tunnel and bed;Step two, according to the measured tunnel settlement, convergence deformation, bed gap correction numerical model;Step three, line void data are obtained by numerical model calculation, form line void information base;Step four, in the process of line, through routine bed gap inspection and / or regular tunnel settlement deformation inspection, and according to void information base, the tunnel void state is identified.The application optimizes tunnel bed numerical model by measured data, establishes void information base, and is combined with existing tunnel monitoring method, can quickly and accurately identify the void state of shield tunnel bed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield tunnel monitoring, in particular to a shield tunnel bed void state identification method. BACKGROUND

[0002] The shield tunnel structure is the main structure form of the subway tunnel, the shield tunnel segment is deeply buried underground, and is affected by various factors such as tunnel settlement and tunnel deformation, so that the tunnel bed is prone to peeling and voiding in varying degrees. The peeling and voiding of the tunnel bed will affect the safety of train operation, so it is necessary to identify the voiding state of the shield tunnel bed in daily and regular inspection. At present, the voiding monitoring of the shield tunnel bed is only through manual caliper measurement of the voiding distance, and the existing detection method is difficult to identify the voiding state of the tunnel bed-tunnel joint surface which is difficult to access.

[0003] Therefore, how to invent a method to quickly and accurately identify the voiding state of the shield tunnel bed has become an urgent need in the industry.

[0004] Through retrieval, an application No. CN201711269120.1, a subway tunnel bed void amount monitoring method, proposes a subway tunnel bed void amount monitoring method, which comprises the following steps: arranging measuring points on the shield segment and the tunnel bed in the tunnel area to be monitored, installing a piezoelectric acceleration sensor at the measuring point position, and recording the vibration of the shield segment and the whole tunnel bed during and after the train runs. The application uses an acceleration sensor and a high-speed dynamic acquisition device to quickly realize the rapid and real-time monitoring of the void amount at the joint between the tunnel bed and the tunnel shield segment. The present application is different from the idea of the invention patent, and the tunnel bed numerical model is optimized by the measured data, the void information database is established, and the existing tunnel monitoring method can be combined and applied. SUMMARY

[0005] The technical problem to be solved by the present application is to solve the deficiencies of the prior art, and to provide a shield tunnel bed void state identification method. The tunnel bed numerical model is optimized by the measured data, the void information database is established, and the existing tunnel monitoring method can be combined and applied to quickly and accurately identify the void state of the shield tunnel bed.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a shield tunnel bed void state identification method, comprising the following steps:

[0007] Step 1, establishing a numerical model of the shield tunnel and the tunnel bed;

[0008] Step 2, correcting the numerical model according to the measured tunnel settlement, convergence deformation and tunnel bed separation;

[0009] Step three, obtain the line void data through the numerical model calculation, and form the line void information library;

[0010] Step four, during the line operation period, the tunnel void state is identified through the daily track bed separation inspection and / or the regular tunnel settlement deformation inspection, and according to the void information library.

[0011] As a further preferred embodiment of the present application, in step one, the corresponding numerical model is established according to the structure form of the shield tunnel and the track bed.

[0012] The shield tunnel segment size and the assembly form in the numerical model are modeled according to the drawings, and the tunnel segment bolt hand hole, the caulking, the chamfer, and the sealing pad groove are ignored during modeling; the track bed height is modeled according to the drawings, and the track bed drainage structure and the like are ignored.

[0013] The shield tunnel and the track bed are connected by using the cohesive force constitutive controlled cohesive element, the numerical model is established as a cohesive force model, and the following initial parameters are set: interface stiffness Normal tensile strength Tangential tensile strength Normal fracture energy Tangential fracture energy

[0014] As a further preferred embodiment of the present application, in step two, the tunnel settlement is measured by using the level gauge and the total station, and the tunnel convergence deformation is measured by using the level gauge, the total station, and the laser scanner.

[0015] The obtained tunnel settlement and the tunnel convergence deformation are taken as the boundary conditions and brought into the numerical model, and the theoretical track bed separation is calculated.

[0016] The actual track bed separation is measured by using the caliper, and the numerical model is optimized according to the actual track bed separation data, the initial parameters of the cohesive force model are modified, the track bed separation calculated by the numerical model is consistent with the measured data, and the cohesive force model consistent with the actual tunnel and track bed structure is obtained through iteration.

[0017] As a further preferred embodiment of the present application, in step three, the numerical model is used to calculate the track bed void under different tunnel settlement and tunnel convergence deformation conditions, obtain the void data, and establish the void information library, the void information library includes the function relationship of the track bed separation-void rate envelope relationship, and the function relationship of the tunnel settlement, the tunnel convergence deformation, and the track bed void rate.

[0018] As a further preferred embodiment of the present application, the function relationship of the track bed separation-void rate envelope relationship is:

[0019] t max =a-b ln(d0+c)

[0020]

[0021] t min ≤t≤t max

[0022] wherein, t is the ballast void ratio, t min is the lower limit value of the void ratio, t max is the upper limit value of the void ratio, d0 is the ballast separation, and the rest are coefficients.

[0023] The coefficients are determined by using a large number of void data obtained by numerical calculation and adopting a regression fitting method.

[0024] As a further preferred embodiment of the present application, the functional relationship between the tunnel settlement, the tunnel convergence deformation and the ballast void ratio is:

[0025] t = a1u + a2u 2 +b1v+b2v 2 +b3v 3 +b4v 4

[0026] wherein, t is the ballast void ratio, u is the tunnel settlement, v is the tunnel convergence deformation, and the rest are coefficients.

[0027] The coefficients are determined by using a large number of void data obtained by numerical calculation and adopting a regression fitting method.

[0028] As a further preferred embodiment of the present application, in step four, the specific method of the daily ballast separation inspection is: in the daily tunnel inspection, the ballast separation is measured by a plug gauge, and according to the left side ballast separation-void ratio envelope relationship and the right side ballast separation-void ratio envelope relationship in the void information database, the upper and lower limit values of the ballast void ratio are quickly identified.

[0029] The specific method of the periodic tunnel settlement deformation inspection is: in the periodic tunnel inspection, the tunnel settlement and deformation are measured by using a level gauge, a total station and a laser scanner, and according to the functional relationship between the tunnel settlement, the tunnel convergence deformation and the left side ballast void ratio and the functional relationship between the tunnel settlement, the tunnel convergence deformation and the right side ballast void ratio in the void information database, the ballast void state of the line is accurately identified.

[0030] The present application has the following beneficial effects:

[0031] 1. The present application provides a shield tunnel ballast void state identification method, which can quickly and accurately identify the void state of the shield tunnel ballast by optimizing the tunnel ballast numerical model through the measured data, establishing a void information database, and combining with the existing tunnel monitoring method.

[0032] 2. This invention has two identification modes: a daily track bed gap inspection mode and a periodic tunnel settlement and deformation inspection mode. The combination of the two modes can realize daily inspection and periodic inspection, and quickly and accurately identify the track bed voiding status and the upper and lower limits of the track bed voiding rate. Attached Figure Description

[0033] Figure 1 This is a flowchart of a method for identifying the void state of a shield tunnel track bed according to the present invention.

[0034] Figure 2 This is a numerical model diagram of a method for identifying the void state of a shield tunnel track bed according to the present invention.

[0035] Figure 3-1 This is an envelope diagram of the left side track bed separation-voidage rate for a shield tunnel track bed voiding state identification method according to the present invention.

[0036] Figure 3-2 This is an envelope diagram of the right-side track bed separation-voidage rate of a shield tunnel track bed voiding state identification method according to the present invention.

[0037] These include: 1. Shield tunnel; 2. Track bed. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0041] Example 1

[0042] like Figure 1 As shown, the basic process of this invention is as follows:

[0043] Step 1: Establish a numerical model of the shield tunnel and track bed;

[0044] Step 2: Correct the numerical model based on the measured tunnel settlement, convergence deformation, and track bed joint separation.

[0045] Step 3: Obtain line clearance data through numerical model calculation to form a line clearance information database;

[0046] Step four, line operation period, through the daily track bed off-seam inspection and / or regular tunnel settlement deformation inspection, and according to the void information base, the tunnel void state is identified.

[0047] The process of establishing the numerical model of the shield tunnel and the track bed is as follows:

[0048] As shown in Figure 2 , the outer diameter of the tunnel is 6.2m, and the inner diameter of the tunnel is 5.5m. The tunnel is longitudinally assembled by 49 rings of segments, and each ring of segments is assembled by 6 segment blocks. A single segment block includes a standard block AT1, a standard block AT2, a standard block AT3, an adjacent block BT1, an adjacent block BT2, and a top sealing block KT. The segments are assembled in a staggered manner along the longitudinal direction, and the longitudinal length of a single ring of segments is 1.2m. The bolt hand hole, the joint, the chamfer, the sealing gasket groove and other structures of the segment are ignored. The top surface of the track bed has a maximum vertical distance of 0.6m from the bottom of the tunnel. The drainage structure and other structures of the track bed are ignored.

[0049] The cohesive unit controlled by the cohesive force constitutive is used to connect the shield tunnel and the track bed, and the cohesive force model is established, and the following initial parameters are set: interface stiffness Normal tensile strength Tangential tensile strength Normal fracture energy Tangential fracture energy

[0050] In step two, the tunnel settlement is measured using the level gauge and total station; the tunnel convergence deformation is measured using the level gauge, total station and laser scanner; the actual track bed off-seam is measured using the plug gauge. According to the measured tunnel settlement and deformation, the tunnel crown and the tunnel soffit in the numerical model are subjected to tunnel settlement, and the tunnel haunch is subjected to tunnel convergence deformation, and the track bed off-seam is calculated. By continuously modifying the parameters of the cohesive force model, the track bed off-seam calculated by the numerical model is consistent with the measured data, and the numerical model is optimized according to the measured track bed off-seam data. Finally, the numerical model consistent with the real tunnel and track bed structure is obtained through repeated iteration.

[0051] The cohesive force model parameters consistent with the measured data obtained through final iteration are: interface stiffness Normal tensile strength Tangential tensile strength Normal fracture energy Tangential fracture energy

[0052] As shown in Figure 3-1 and 3-2As shown, in step three, using numerical model, a large number of calculations of ballast voiding conditions under different tunnel settlement and tunnel convergence deformation conditions are carried out to obtain voiding information and establish a line voiding information library. According to the cohesion model and input initial parameters, the regression fitting method is finally used to determine the function coefficients in the voiding information library, and the coefficients are calculated known quantities.

[0053] In the voiding information library of the embodiment, the envelope relationship between the left side ballast of the tunnel running direction and the gap-voiding rate is:

[0054] t L max = 0.49 + 0.12ln(d 0L + 0.02)

[0055]

[0056] t L min ≤t L ≤t L max

[0057] Among them, t L is the left side ballast voiding rate, t L min is the lower limit value of the left side voiding rate, t L max is the upper limit value of the left side voiding rate, and d 0L is the left side ballast gap.

[0058] The envelope relationship between the right side ballast of the tunnel running direction and the gap-voiding rate is:

[0059] t R max = 0.51 + 0.12ln d 0R

[0060]

[0061] t R min ≤t R ≤t R max

[0062] Among them, t R is the right side ballast voiding rate, t R min is the lower limit value of the right side voiding rate, t R max is the upper limit value of the right side voiding rate, and d 0R is the right side ballast gap.

[0063] In the voiding information library of the embodiment, the functional relationship between the tunnel settlement, the tunnel convergence deformation and the left side ballast voiding rate is:

[0064] t L = -0.0114u + 2.86x10 -4 u 2 + 0.0983v - 0.00578v 2+ 4.22 x 10 -6 v 4

[0065] Wherein, t L is the left side ballast void rate, u is the tunnel settlement, and v is the tunnel convergence deformation.

[0066] The functional relationship between the tunnel settlement, the tunnel convergence deformation, and the right side ballast void rate is:

[0067] t R = -0.0210u + 2.03 x 10 -5 u 3 + 0.160v - 0.00262v 2

[0068] Wherein, t R is the right side ballast void rate, u is the tunnel settlement, and v is the tunnel convergence deformation.

[0069] In step four, the ballast void state recognition mode is divided into a daily ballast separation inspection mode and a regular tunnel settlement deformation inspection mode. The daily ballast separation inspection mode is mode one, and the regular tunnel settlement deformation inspection mode is mode two.

[0070] The specific method of the ballast void state recognition mode one is as follows: in the daily tunnel inspection, the ballast separation d0 is measured by using a caliper, and the upper and lower limit values of the ballast void rate are quickly recognized according to the envelope relationship between the left and right side ballast separation-void rates in the void information database.

[0071] The specific method of the ballast void state recognition mode two is as follows: in the regular tunnel inspection, the tunnel settlement and deformation are measured by using a level, a total station, a laser scanner, and the like, and the ballast void state of the line is accurately recognized according to the functional relationship between the tunnel settlement, the tunnel convergence deformation, and the left and right side ballast void rates in the void information database.

[0072] The preferred embodiments of the application are described in detail above, but the application is not limited to the specific details in the above-described embodiments. Within the technical concept range of the application, various equivalent transformations can be made to the technical solutions of the application, and these equivalent transformations all belong to the protection range of the application.

Claims

1. A method for identifying the void state of the track bed in a shield tunnel, characterized in that: Includes the following steps: Step 1: Establish a numerical model of the shield tunnel and track bed; Step 2: Correct the numerical model based on the measured tunnel settlement, convergence deformation, and track bed joint separation. Step 3: Obtain track clearance data through numerical model calculation to form a track clearance information database: Using numerical models, calculate the track bed clearance under different tunnel settlement and tunnel convergence deformation conditions, obtain clearance data, and establish a clearance information database. The clearance information database includes the functional relationship of the track bed joint-clearance rate envelope, as well as the functional relationship between tunnel settlement, tunnel convergence deformation, and track bed clearance rate; The functional relationship of the track bed gap-void rate envelope is as follows: in, For the track bed clearance rate, This is the lower limit of the emptying rate. This is the upper limit of the emptying rate. The distance between the track bed and the joint is the standard distance; the rest are coefficients. The coefficients were determined using a large amount of empty data obtained through numerical calculations and a regression fitting method. Step four: During the track preparation process, routine inspections of track bed joint gaps and / or periodic tunnel settlement and deformation checks are conducted, and adjustments are made based on the findings. An empty information database is used to identify the state of tunnel caving.

2. The method for identifying the void state of the shield tunnel track bed according to claim 1, characterized in that: In step one, a corresponding numerical model is established based on the structural form of the shield tunnel and the track bed; In the numerical model, the dimensions and assembly form of the shield tunnel segments are modeled according to the drawings, ignoring the bolt manholes, caulking, chamfering, and sealing gasket grooves of the tunnel segments; the track bed height is modeled according to the drawings, ignoring the track bed drainage structure. A cohesive model was established by connecting the shield tunnel and the track bed using bonding elements controlled by cohesive constitutive modeling, and the following initial parameters were set: interface stiffness. Normal tensile strength tangential tensile strength Normal fracture energy tangential fracture energy .

3. The method for identifying the void state of the shield tunnel track bed according to claim 2, characterized in that: In step two, the tunnel settlement was measured using a level and a total station; the tunnel convergence deformation was measured using a level, a total station, and a laser scanner. The obtained tunnel settlement and tunnel convergence deformation were used as boundary conditions and substituted into the numerical model to calculate the theoretical track bed separation joint. The actual track bed gap was measured using a feeler gauge, and the numerical model was optimized based on the actual track bed gap data. By modifying the initial parameters of the cohesion model, the track bed gap calculated by the numerical model was made consistent with the measured data. Through iteration, a cohesion model that conforms to the actual tunnel and track bed structure was obtained.

4. The method for identifying the void state of the shield tunnel track bed according to claim 1, characterized in that: The functional relationship between tunnel settlement, tunnel convergence deformation, and track bed voiding rate is as follows: Where t is the track bed void ratio, u is the tunnel settlement, v is the tunnel convergence deformation, and the rest are coefficients; The coefficients were determined using a large amount of empty data obtained through numerical calculations and a regression fitting method.

5. The method for identifying the void state of the shield tunnel track bed according to claim 1, characterized in that: In step four, the specific method for routine track bed gap inspection is as follows: During routine tunnel inspection, the track bed gap is measured using a feeler gauge. Based on the gap information database, the upper and lower limits of the track bed gap rate are quickly identified. The specific methods for regular tunnel settlement and deformation inspection are as follows: During regular tunnel inspections, a level, total station, and laser instrument are used. The scanner measures the tunnel settlement and deformation. Based on the functional relationships between tunnel settlement, tunnel convergence deformation and the voiding rate of the left track bed and tunnel settlement, tunnel convergence deformation and the voiding rate of the right track bed in the voiding information database, the voiding status of the track bed of the line is accurately identified.

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