A method and system for calculating the settlement of a immersed tube tunnel under the load of siltation and a medium

Abstract

The present application relates to the technical field of immersed tube tunnel, and particularly relates to a method and system for calculating the settlement of an immersed tube tunnel under siltation load and a medium, the method comprising: making a basic assumption based on the stress deformation characteristics of the immersed tube tunnel, determining the cycle form of the siltation load based on the basic assumption, and obtaining a calculation expression of the siltation load changing with time; calculating the nonlinear consolidation settlement of the underlying ground soil layer caused by the siltation load; obtaining a calculation expression of the ground settlement changing with time by means of the compression modulus, drainage distance, consolidation coefficient and cycle period of the ground soil layer, and combining the Taylor expansion formula; determining the deflection of the immersed tube tunnel under different dredging frequencies based on the bending moment and shear force of the Timoshenko beam model; and determining the settlement value at the left end joint of any tube segment and the settlement value at the right end joint of any tube segment according to the transmission deflection difference and the rotation angle between adjacent tube segments in the immersed tube tunnel; the present application can improve the calculation accuracy of the settlement of the immersed tube tunnel caused by siltation.

Description

Technical Field

[0001] The present invention relates to the technical field of immersed tube tunnels, and in particular to a method, system and medium for calculating the settlement of an immersed tube tunnel under siltation load. Background Art

[0002] In modern cross-sea projects, immersed tube tunnels have become a widely used solution due to their short construction periods, excellent waterproofing, and strong geological adaptability. Compared to traditional immersed tube tunnels, shallow-buried immersed tube tunnels are relatively simple to construct and maintain. However, they are often subject to siltation loads during operation and maintenance. The impact of siltation loads on tunnel deformation, particularly during the operation and maintenance period, has not been fully studied. In recent years, with the accelerated construction of coastal and waterway systems in my country, many immersed tube tunnels have crossed busy waterways, many of which are deep-buried. In such cases, pipe segments are subject to more complex siltation loads during operation. Studies have found that siltation rates can reach as high as 5 cm / d⁻¹, and segment settlement caused by siltation loads accounts for approximately 13% of total settlement. This is particularly true at segment joints, where differential settlement has a significant impact on the structure. Differences in settlement at segment joints can lead to localized uneven settlement, which can easily cause excessive settlement or fatigue damage in immersed tube tunnel joints, further compromising the safety of the tunnel structure. Therefore, studying the long-term settlement of immersed tube tunnels under siltation loads during the operation and maintenance period has important theoretical and practical significance.

[0003] Most existing research focuses on tunnel bending and shear deformation, but the differential displacement at pipe joints is often overlooked. Displacement differentials at pipe joints have a crucial impact on the overall stability and safety of the tunnel. Ignoring this can lead to inaccurate assessments of tunnel deformation, thereby underestimating or ignoring potential risks. Therefore, there is a need to improve the accuracy of settlement calculations for sunken tube tunnels under siltation loads. Summary of the Invention

[0004] The present invention aims to provide a method, system and medium for calculating the settlement of an immersed tube tunnel under siltation load, so as to improve the calculation accuracy of the settlement of an immersed tube tunnel caused by siltation.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a method for calculating the settlement of an immersed tunnel under siltation load, the method comprising the following steps:

[0007] S100, obtaining stress and deformation characteristics of the immersed tube tunnel, making basic assumptions based on the stress and deformation characteristics of the immersed tube tunnel, determining the cyclic form of the sedimentation load based on the basic assumptions, and obtaining a calculation expression for the variation of the sedimentation load with time;

[0008] S200, calculating the nonlinear consolidation settlement of the underlying ground layer caused by the silt load based on the Terzaghi one-dimensional consolidation theory differential equation; through the compression modulus, drainage distance, consolidation coefficient and cycle period of the ground layer, and combining the Taylor expansion formula, a calculation expression of the ground settlement changing with time is obtained;

[0009] S300, determining the bending moment and shear force of the immersed tube tunnel under the Timoshenko beam model, and determining the deflection of the immersed tube tunnel under different dredging frequencies based on the bending moment and shear force of the Timoshenko beam model;

[0010] S400, determining the transmission deflection difference between adjacent pipe sections in the immersed tube tunnel based on the deflection of the immersed tube tunnel, and determining the settlement value at the left end joint of any pipe section and the settlement value at the right end joint of any pipe section according to the transmission deflection difference and the rotation angle between adjacent pipe sections in the immersed tube tunnel.

[0011] Optionally, in S200, the basic assumptions are made based on the stress deformation characteristics of the immersed tube tunnel, including:

[0012] A flexible beam model of the immersed tube tunnel is constructed based on the stress deformation characteristics;

[0013] The immersed tube tunnel is assumed to be placed on a Vlasov double-parameter foundation, and the soil stiffness is set as a constant or a function changing with the depth of the foundation; wherein the Vlasov double-parameter foundation has continuity and its stiffness changes with the depth;

[0014] The silt load is assumed to change periodically with time, i.e. periodically increasing and decreasing;

[0015] And the deformation of the pipe section is modeled through the dislocation deformation mode, and the deformation of the pipe section includes bending deformation and shear deformation.

[0016] Optionally, the calculation expression of the silt load changing with time is:

[0017]

[0018] Wherein, q(t) is the silt load in any time period, t is the loading time length in any time period; Q0 is the initial load; α t is the accumulated silt load increasing linearly with time, and α is the accumulation rate; ΔL is the load drop caused by each dredging event; represents the number of dredging completed in time t, represents the floor function; T q is the dredging period, and subscript q represents the number of the dredging period, and q is a positive integer. The calculation expression of the dredging period is:

[0019]

[0020] Among them, n is the number of silt removals in a year, that is, the silt removal frequency.

[0021] Optionally, in S200, the calculation expression for the change of foundation settlement over time is derived by combining the compression modulus, drainage distance, consolidation coefficient, and cycle period of the foundation soil layer with a Taylor expansion, including:

[0022] The consolidation coefficient c of the foundation v Considered as constant, the Terzaghi one-dimensional consolidation theory differential equation is introduced:

[0023]

[0024] Among them, c v , z, and u are the consolidation coefficient of the foundation, soil depth, and excess pore water pressure, respectively; f(t) is the load loading rate;

[0025] Based on the orthogonal relationship of trigonometric functions and the inverse Laplace transform, and referring to the analytical solution of one-dimensional nonlinear consolidation of soil under continuous drainage boundary conditions, the foundation settlement S(t) at time t is calculated using the following formula:

[0026]

[0027] Where A=H / E S , B=2 / M; H is the drainage distance; E S is the compression modulus of the foundation; M = (2a-1)π / 2, a is a positive integer; N is the number of complete load cycles; T m1 (t), T m2 (t) is the time function to be calculated, m is the index of the summation; T q is the load cycle period; i, j are the accumulated indexes; βT q The adjustment factor for the time interval is used to scale the time offset of the accumulated items.

[0028] Optionally, in S300, the calculation method for determining the deformation of the pipe segment under different dredging frequencies based on the bending moment expression and the shear force expression of the Timoshenko beam model includes:

[0029] Determine the cross-sectional rotation angle of the beam based on the deflection and shear strain of the beam, and determine the bending moment of the Timoshenko beam model that varies with position based on the cross-sectional rotation angle, elastic modulus, and moment of inertia of the beam;

[0030] The shear strain of the beam is determined based on the deflection, the cross-section rotation angle and the shear coefficient of the beam, and the shear force varying with the position of the Timoshenko beam model is determined based on the shear strain of the beam, the shear modulus and the effective area of the beam;

[0031] The deflection of the immersed tunnel is obtained based on the bending moment and the shear force of the Timoshenko beam model.

[0032] Optionally, the deflection of the immersed tunnel is obtained by the following formula:

[0033]

[0034] wherein s is the deflection of the immersed tunnel, T k is the prestress generated in the construction process of the immersed tunnel; EI and GA are the bending stiffness and shear stiffness of the pipe section respectively, K is the curvature of the neutral axis, ds / dx is the rotation angle of the neutral axis, i.e. θ, is the bending rotation angle, is the cross-section shear angle caused by the shear deformation, i.e. γ, f s is the non-uniform distribution coefficient of the cross-section shear stress; α, β and γ are all intermediate quantities; P(t) is the load.

[0035] Optionally, the expression of the load is:

[0036] P(t)=q(t)·B;

[0037] wherein q(t) is the accumulated load, and B is the lateral width of the pipe section;

[0038] The expression of the deflection of the right end of the pipe section is:

[0039]

[0040] wherein s0 is the initial deflection, θ0 is the initial rotation angle, M0 is the initial bending moment, and Q0 is the initial shear force;

[0041] The bending moment of the immersed tunnel is obtained based on the bending moment of the Timoshenko beam model and the deflection of the right end of the pipe section.

[0042] The expression of the bending moment of the immersed tunnel is:

[0043]

[0044] According to the relationship between the bending moment and the shear force, the shear force of the immersed tunnel is obtained.

[0045] The expression of the shear force of the immersed tunnel is:

[0046]

[0047] Among them, M(x) and Q(x) are the bending moment and shear force of the immersed tube tunnel, respectively.

[0048] Optionally, in S400, determining the settlement value at the left end joint of any pipe segment and the settlement value at the right end joint of any pipe segment based on the transfer deflection difference and the rotation angle between adjacent pipe segments of the immersed tunnel includes:

[0049] The transfer deflection difference Δs and rotation angle Δθ between adjacent tube segments in an immersed tunnel are calculated using the following formula:

[0050] Δs=Q(i) / k j ;

[0051] Δθ=M(i) / k W ;

[0052] Where Δs is the transfer deflection difference between adjacent segments of the immersed tunnel, Δθ is the rotation angle between adjacent segments of the immersed tunnel, Q(i) and M(i) are the shear force between the i-th segment and the i-1-th segment and the immersed tunnel bending moment, respectively. j and k w are the shear stiffness and bending stiffness of the joint respectively;

[0053] The sum of the settlement value at the right end of the previous pipe segment and the transfer deflection difference between the adjacent joints of the previous pipe segment is taken as the settlement value at the left end joint of the current pipe segment, and the sum of the settlement value at the left end of the pipe segment and the deflection value of the pipe segment is taken as the settlement value at the right end joint of the current pipe segment.

[0054] In a second aspect, an embodiment of the present invention provides a system for calculating the settlement of an immersed tunnel under siltation load, the system comprising:

[0055] at least one processor;

[0056] at least one memory for storing at least one program;

[0057] When the at least one program is executed by the at least one processor, the at least one processor implements the method for calculating the settlement of an immersed tunnel under siltation load as described in any one of the above.

[0058] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium storing a program executable by a processor, which, when executed by the processor, is used to execute the method for calculating the settlement of an immersed tube tunnel under siltation load as described in any one of the above.

[0059] The present invention provides a method, system, and medium for calculating the settlement of an immersed tube tunnel under siltation loads. Based on the Vlasov two-parameter foundation model and the Timoshenko beam model, and by considering the continuity of the foundation soil and the shear deformation of the immersed tube structure, a calculation method is established that accurately predicts the long-term settlement of an immersed tube tunnel under cyclic siltation loads. The method is simple to operate and highly cost-effective, helping monitoring personnel optimize the design and management of immersed tube tunnels, prepare for settlement and deformation in advance, and improve the long-term safety of immersed tube tunnels. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in 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 paying any creative work.

[0061] Figure 1 1 is a flow chart of a method for calculating the settlement of an immersed tube tunnel under siltation load in an embodiment of the present invention;

[0062] Figure 2 is a function diagram showing the trend of sedimentation load changing with time in the present invention;

[0063] Figure 3 This is a schematic diagram of an immersed tube tunnel in a certain engineering example provided by an embodiment of the present invention;

[0064] Figure 4 yes Figure 3 Curve diagram of the change of sedimentation load on the immersed tube tunnel;

[0065] Figure 5 yes Figure 3 Comparison chart of model calculation and measured data of immersed tube tunnel;

[0066] Figure 6 yes Figure 3 Comparison chart of the difference between the calculated and measured data of the immersed tube tunnel model;

[0067] Figure 7 4 is a structural diagram of a system for calculating the settlement of an immersed tunnel under siltation load in an embodiment of the present invention. DETAILED DESCRIPTION

[0068] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other unless there is a conflict.

[0069] In order to solve the technical problems in the background technology, the embodiment provided by the present invention analyzes the stress and deformation of tunnel joints based on the Timoshenko beam model, and carries out joint stress analysis based on the Timoshenko beam model to improve the accuracy of predicting the settlement deformation of immersed tube tunnels, thereby improving the safety and reliability of long-term operation of the tunnel.

[0070] See Figure 1 , Figure 1 The present invention provides a method for calculating the settlement of an immersed tube tunnel under siltation load, the method comprising the following steps:

[0071] S100, obtaining stress and deformation characteristics of the immersed tube tunnel, making basic assumptions based on the stress and deformation characteristics of the immersed tube tunnel, determining the cyclic form of the sedimentation load based on the basic assumptions, and obtaining a calculation expression for the variation of the sedimentation load with time;

[0072] S200 calculates the nonlinear consolidation settlement of the underlying foundation soil layer caused by silt load based on the Terzaghi one-dimensional consolidation theory differential equation. The time-varying expression for foundation settlement is derived by combining the compression modulus, drainage distance, consolidation coefficient, and cyclic period of the foundation soil layer with the Taylor expansion.

[0073] S300, determining the bending moment and shear force of the sunken tube tunnel under the Timoshenko beam model, and determining the deflection of the sunken tube tunnel under different desilting frequencies based on the bending moment and shear force of the Timoshenko beam model;

[0074] Specifically, after determining the bending moment and shear force of the immersed tube tunnel under the Timoshenko beam model, the deflection under different desilting frequencies was determined, and the deformation of the pipe segments of the immersed tube tunnel was obtained.

[0075] S400, determining the transferred deflection difference between adjacent pipe sections in the immersed tunnel based on the deflection of the immersed tunnel, and determining the settlement value at the left end joint of any pipe section and the settlement value at the right end joint of any pipe section according to the transferred deflection difference and the rotation angle between adjacent pipe sections in the immersed tunnel.

[0076] In the embodiment provided by the present invention, based on the stress and deformation characteristics of the flexible immersed tube tunnel under load, the tunnel pipe segment is simplified into a Timoshenko beam and placed on the Vlasov two-parameter foundation model, and the continuity of the foundation soil and the enhancement of the soil stiffness are taken into account. The invention further considers the bending and shear deformation of the pipe segment, adopts the dislocation deformation mode to model the deformation of the pipe segment, and derives the calculation formula for vertical settlement. Combined with actual working conditions, the settlement value at the left end joint of each pipe segment and the settlement value at the right end joint of each pipe segment can be determined according to the transfer deflection difference and rotation angle between adjacent pipe segments of the immersed tube tunnel. The invention is simple to operate, has high economic benefits, can provide strong support for tunnel design and management, and help monitoring personnel to timely predict the settlement deformation of the immersed tube tunnel, thereby improving the safety and reliability of the long-term operation of the tunnel.

[0077] In some embodiments, in S200, making basic assumptions based on the stress and deformation characteristics of the immersed tunnel includes:

[0078] constructing a flexible beam model of the immersed tunnel based on the stress-deformation characteristics;

[0079] Specifically, the immersed tube tunnel behaves as a flexible structure under load, so the immersed tube tunnel can be simplified as a flexible beam and the rigidity effect of the structure can be ignored;

[0080] Assuming that the immersed tunnel is placed on a Vlasov two-parameter foundation, the soil stiffness is set to be a constant or a function that varies with the foundation depth; wherein the Vlasov two-parameter foundation is continuous and its stiffness varies with depth;

[0081] Specifically, the immersed tunnel is placed on a Vlasov two-parameter foundation, assuming that the foundation soil is continuous and its stiffness varies with depth. The soil stiffness can be considered as a constant or a function that varies with the foundation depth;

[0082] It is assumed that the sedimentation load changes with time in a cyclical manner;

[0083] In this step, it is assumed that the distribution of the sedimentation load follows the periodic characteristics of time variation, and the variation of the sedimentation load is assumed to conform to the typical cyclic law of the sedimentation load;

[0084] The deformation of the pipe segment is modeled by a dislocation deformation mode, wherein the deformation of the pipe segment includes bending deformation and shear deformation.

[0085] Specifically, the deformation of the pipe segment mainly manifests as bending deformation and shear deformation, and the deformation of the pipe segment can be modeled by the dislocation deformation mode.

[0086] In some embodiments, the calculation expression of the sedimentation load changing with time is:

[0087]

[0088] Where q(t) is the sedimentation load in any time period, t is the loading duration in any time period; Q0 is the initial load; α t is the cumulative load of silt that increases linearly with time, α is the accumulation rate; ΔL is the load reduction caused by each silt removal event; represents the number of desilting operations completed within time t, Indicates rounding down; T q is the desilting cycle, the subscript q represents the desilting cycle number, and q is a positive integer. It indicates a specific desilting cycle. The calculation expression of the desilting cycle is:

[0089]

[0090] Among them, n is the number of silt removals in a year, that is, the silt removal frequency.

[0091] In some embodiments, in S200, the calculation expression for the change of foundation settlement over time is derived by combining the compression modulus, drainage distance, consolidation coefficient, and cycle period of the foundation soil layer with the Taylor expansion, including:

[0092] The consolidation coefficient c of the foundation v Considered as constant, the Terzaghi one-dimensional consolidation theory differential equation is introduced:

[0093]

[0094] Among them, c v , z, and u are the consolidation coefficient of the foundation, soil depth, and excess pore water pressure, respectively; f(t) is the load loading rate;

[0095] Based on the orthogonal relationship of trigonometric functions and the inverse Laplace transform, and referring to the analytical solution of one-dimensional nonlinear consolidation of soil under continuous drainage boundary conditions, the foundation settlement S(t) at time t is calculated using the following formula:

[0096]

[0097] Where A=H / E S , B=2 / M; H is the drainage distance; E S is the compression modulus of the foundation; M = (2a-1)π / 2, a is a positive integer; N is the number of complete load cycles; T m1 (t), T m2 (t) is the time function to be calculated, m is the index of the summation; T q is the load cycle period; i, j are the accumulated indexes; βT qThe adjustment factor for the time interval is used to scale the time offset of the accumulated items.

[0098] In some embodiments, in S300, the calculation method for determining the deformation of the pipe segment under different dredging frequencies based on the bending moment expression and the shear force expression of the Timoshenko beam model includes:

[0099] Determine the cross-sectional rotation angle of the beam based on the deflection and shear strain of the beam, and determine the bending moment of the Timoshenko beam model that varies with position based on the cross-sectional rotation angle, elastic modulus, and moment of inertia of the beam;

[0100] Determine the shear strain of the beam based on the deflection, cross-section rotation angle, and shear coefficient of the beam, and determine the position-dependent shear force of the Timoshenko beam model based on the shear strain, shear modulus, and effective area of ​​the beam;

[0101] The deflection of the immersed tunnel is obtained based on the bending moment and shear force of the Timoshenko beam model.

[0102] In some embodiments, the deflection of the immersed tunnel is calculated using the following formula:

[0103]

[0104]

[0105] Where s is the deflection of the immersed tunnel, T k is the prestress generated during the construction of the immersed tube tunnel; EI and GA are the bending stiffness and shear stiffness of the tube segment, respectively; K is the curvature of the neutral axis; ds / dx is the rotation angle of the neutral axis, i.e., θ. For the turning angle, is the cross-sectional shear angle caused by shear deformation, i.e., γ, f s is the non-uniform distribution coefficient of cross-sectional shear stress; α, β and γ are all intermediate quantities; P(t) is the load.

[0106] In some embodiments, the load is expressed as:

[0107] P(t) = q(t)·B;

[0108] Where q(t) is the sedimentation load, B is the transverse width of the pipe segment;

[0109] The expression for the deflection of the right end of the pipe segment is:

[0110]

[0111] Where, s0 is the initial deflection; θ0 is the initial rotation angle; M0 is the initial bending moment; Q0 is the initial shear force;

[0112] The bending moment of the immersed tube tunnel is obtained based on the bending moment of the Timoshenko beam model and the deflection of the right end of the tube segment;

[0113] The bending moment expression of immersed tube tunnel is:

[0114]

[0115] According to the relationship between bending moment and shear force, the shear force of the immersed tube tunnel is obtained;

[0116] The shear force expression of immersed tube tunnel is:

[0117]

[0118] Among them, M(x) and Q(x) are the bending moment and shear force of the immersed tube tunnel, respectively.

[0119] In some embodiments, in S400, determining the settlement value at the left end joint of any pipe segment and the settlement value at the right end joint of any pipe segment based on the transfer deflection difference and the rotation angle between adjacent pipe segments of the immersed tube tunnel includes:

[0120] The transfer deflection difference Δs and rotation angle Δθ between adjacent tube segments in an immersed tunnel are calculated using the following formula:

[0121] Δs=Q(i) / k j ;

[0122] Δθ=M(i) / k W ;

[0123] Where Δs is the transfer deflection difference between adjacent segments of the immersed tunnel, Δθ is the rotation angle between adjacent segments of the immersed tunnel, Q(i) and M(i) are the shear force between the i-th segment and the i-1-th segment and the immersed tunnel bending moment, respectively. j and k w are the shear stiffness and bending stiffness of the joint respectively;

[0124] The settlement value at the left end joint of the pipe segment is calculated using the following formula:

[0125] W i- =W (i-1)+ +Δs (i-1) ;

[0126] Among them, W i- is the settlement value at the left end joint of the i-th pipe segment, W (i-1)+ is the settlement value at the right end joint of the i-1th pipe segment, Δs (i-1) is the difference in transfer deflection between the adjacent joints of the i-th pipe segment and the i-1-th pipe segment;

[0127] The settlement value at the right end joint of the pipe segment is calculated using the following formula:

[0128] W i+ =W i- +s i ;

[0129] Among them, W i+ is the settlement value at the right end joint of the i-th pipe segment, s i is the deflection value of the i-th pipe segment.

[0130] It should be noted that if Δs is a positive number, it indicates that the subsequent pipe segment has settled relative to the previous one; if Δs is a negative number, it indicates that the subsequent pipe segment has risen relative to the previous one. If Δθ is a positive number, it indicates that the pipe segment has rotated clockwise; if Δθ is a negative number, it indicates that the pipe segment has rotated counterclockwise. The settlement value at the left end joint of any pipe segment is the sum of the settlement value at the right end of the previous pipe segment and the difference in transferred deflection between the adjacent joints of the previous pipe segment. The settlement value at the right end joint of any pipe segment is the sum of the settlement value at the left end of the pipe segment and the deflection value of the pipe segment.

[0131] The following is a specific experiment to illustrate the settlement calculation method of the immersed tube tunnel provided by the present invention:

[0132] A certain immersed tube tunnel has a tunnel length of 1019.97m and a total immersed tube length of 420m. The immersed tube consists of 5 sections, which are marked as E1 to E5 (85m+80m+85m×3) from north to south. Figure 3 The maximum flow velocity of the river is 1.2-1.3 m / s, with an average velocity of 0.36-0.37 m / s. The river is high in sediment and has severe siltation, with a measured siltation intensity of 3 cm / day. This sediment is primarily brought in from the open sea by rising tides, a phenomenon known as sediment backflow. To prevent siltation from causing excessive subsidence in the pipe section, the tunnel management department conducts silt removal twice a year, each desilting process lasting approximately two weeks.

[0133] According to step S100, it is assumed that the siltation load is a trapezoidal cyclic function such as Figure 2 As shown, the relevant parameters are determined as α = 0.5, β = 1.0, and γ = 0.9. Based on the twice-yearly desilting frequency, T = 182.5 days, where d represents the number of days. Based on the measured sedimentation intensity, the maximum value of the cyclic load function, q(tu), = 16.425 kPa can be obtained. Based on the Timoshenko beam model (VT settlement model) for the Vlasov dual-parameter foundation proposed in this invention, the basic parameters of the calculation model are obtained.

[0134] According to step S200, the nonlinear consolidation settlement of the underlying foundation soil layer caused by this is calculated based on the Terzaghi one-dimensional consolidation theory differential equation. The joint is made of rubber material. Within the range of the working water pressure range, the bending stiffness ratio of the joint to the pipe body is 1 / 600, the shear stiffness ratio is 1 / 50, and the joint bending stiffness k is taken. w =3.2×106kN·m / rad, shear stiffness k j =1.1×106kN / m, the shear correction coefficient fs of the beam section is taken as 2.0.

[0135]

[0136] The sedimentation load changes on a certain immersed tube tunnel section are as follows: Figure 4 shown.

[0137] According to step S300, for the calculation model based on the one-dimensional nonlinear consolidation settlement theory of the underlying soil layer (one-dimensional settlement model), the bending moment of the immersed tube tunnel can be calculated by combining the bending moment expression M(x) of the Timoshenko beam model with the deflection expression s of the right end of the tube segment:

[0138]

[0139] According to the relationship between bending moment and shear force, the shear force of the immersed tube tunnel is obtained as:

[0140]

[0141] Through MATLAB fitting, we can get the curve of vertical displacement of pipe joint section changing with time, as shown in the following figure: Figure 5 As shown, compared with the one-dimensional settlement model, the settlement model used in the present invention is more consistent with the measured settlement.

[0142] According to step S400, the settlement value W at the left end joint of any pipe segment i- is the settlement value W at the right end of the previous pipe segment (i-1)+ and the difference in transfer deflection Δs between the adjacent joints of the previous pipe segment (i-1) sum:

[0143] W i- =W (i-1)+ +Δs (i-1) ;

[0144] At the same time, the settlement value W at the right end joint of any pipe segment i+ is the settlement value W at the left end of the pipe segment i- And the deflection value of the pipe segment s i sum:

[0145] W i+ =W i-+s i ;

[0146] The settlement value of the V-T model is obtained by calculation. The settlement difference between the V-T model and the measured data is shown in the one-dimensional settlement model and the measured data, as shown in Figure 6 Compared with the one-dimensional settlement model, the settlement model used in the application has smaller error and is closer to the measured data.

[0147] In summary, through the Timoshenko beam model based on the Vlasov double-parameter foundation model, the fitting degree of the calculation result of the joint deformation and the measured data is good, and the settlement result can be better predicted by calculation.

[0148] Corresponding to the method of Figure 1 , with reference to Figure 7 , the embodiment of the application provides a pipe jacking tunnel settlement calculation system under silt load, which comprises:

[0149] At least one processor;

[0150] At least one memory for storing at least one program;

[0151] When the at least one program is executed by the at least one processor, the at least one processor implements the above-mentioned method.

[0152] It can be seen that the contents in the above-mentioned method embodiment are all applicable to the system embodiment, the system embodiment specifically realizes the same functions as the above-mentioned method embodiment, and achieves the same beneficial effects as the above-mentioned method embodiment.

[0153] In addition, the embodiment of the application also discloses a computer program product or a computer program, which is stored in a computer readable storage medium. The processor of the computer device can read the computer program from the computer readable storage medium, and the processor executes the computer program, so that the computer device executes the above-mentioned method. Similarly, the contents in the above-mentioned method embodiment are all applicable to the storage medium embodiment, the storage medium embodiment specifically realizes the same functions as the above-mentioned method embodiment, and achieves the same beneficial effects as the above-mentioned method embodiment.

[0154] Those skilled in the art will appreciate that all or some of the methods disclosed above, the system can be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, and the computer-readable medium can include computer storage media (or non-transitory media) and communication media (or temporary media). As known to those skilled in the art, the term computer storage media is included in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data) and is volatile and non-volatile, removable and non-removable media. Computer storage media includes but is not limited to RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, as is well known to those skilled in the art, communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0155] The above is a specific description of the preferred implementation of the present disclosure, but the present disclosure is not limited to the above-mentioned implementation mode. Technical personnel familiar with the art can also make various equivalent modifications or substitutions without violating the spirit of the present disclosure. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present disclosure.

Claims

1. A method for calculating the settlement of an immersed tunnel under siltation load, characterized in that: The method comprises the following steps: S100, obtaining stress and deformation characteristics of the immersed tube tunnel, making basic assumptions based on the stress and deformation characteristics of the immersed tube tunnel, determining the cyclic form of the sedimentation load based on the basic assumptions, and obtaining a calculation expression for the variation of the sedimentation load with time; S200 calculates the nonlinear consolidation settlement of the underlying foundation soil layer caused by silt load based on the Terzaghi one-dimensional consolidation theory differential equation. The time-varying expression for foundation settlement is derived by combining the compression modulus, drainage distance, consolidation coefficient, and cyclic period of the foundation soil layer with the Taylor expansion. S300, determining the bending moment and shear force of the sunken tube tunnel under the Timoshenko beam model, and determining the deflection of the sunken tube tunnel under different desilting frequencies based on the bending moment and shear force of the Timoshenko beam model; S400, determining a transferred deflection difference between adjacent pipe sections in the immersed tunnel based on the deflection of the immersed tunnel, and determining a settlement value at a left end joint of any pipe section and a settlement value at a right end joint of any pipe section based on the transferred deflection difference and the rotation angle between the adjacent pipe sections in the immersed tunnel; The method of determining the settlement value at the left end joint of any pipe segment and the settlement value at the right end joint of any pipe segment based on the transfer deflection difference and the rotation angle between adjacent pipe segments in the immersed tube tunnel includes: The transfer deflection difference Δs and rotation angle Δθ between adjacent tube segments in an immersed tunnel are calculated using the following formula: Δs=Q(i) / kj; Δθ=M(i) / k W ; Where Δs is the transfer deflection difference between adjacent segments of the immersed tunnel, Δθ is the rotation angle between adjacent segments of the immersed tunnel, Q(i) and M(i) are the shear force between the i-th segment and the i-1-th segment and the immersed tunnel bending moment, respectively. j and k w are the shear stiffness and bending stiffness of the joint respectively; The sum of the settlement value at the right end of the previous pipe segment and the transfer deflection difference between the adjacent joints of the previous pipe segment is taken as the settlement value at the left end joint of the current pipe segment, and the sum of the settlement value at the left end of the pipe segment and the deflection value of the pipe segment is taken as the settlement value at the right end joint of the current pipe segment.

2. The method for calculating the settlement of an immersed tunnel under siltation load according to claim 1, characterized in that: In S100, the basic assumptions made based on the stress and deformation characteristics of the immersed tube tunnel include: constructing a flexible beam model of the immersed tunnel based on the stress-deformation characteristics; Assuming that the immersed tunnel is placed on a Vlasov two-parameter foundation, the soil stiffness is set to be a constant or a function that varies with the foundation depth; wherein the Vlasov two-parameter foundation is continuous and its stiffness varies with depth; It is assumed that the sedimentation load changes with time in a cyclical manner; The deformation of the pipe segment is modeled by a dislocation deformation mode, wherein the deformation of the pipe segment includes bending deformation and shear deformation.

3. The method for calculating the settlement of an immersed tunnel under siltation load according to claim 2, characterized in that: The calculation expression of the sedimentation load changing with time is: Where q(t) is the sedimentation load in any time period, t is the loading duration in any time period; Q0 is the initial load; α t is the cumulative load of silt that increases linearly with time, α is the accumulation rate; ΔL is the load reduction caused by each silt removal event; represents the number of desilting operations completed within time t, Indicates rounding down; T q is the desilting cycle, the subscript q represents the number of the desilting cycle, and the calculation expression of the desilting cycle is: Among them, n is the number of silt removals in a year, that is, the silt removal frequency.

4. The method for calculating the settlement of an immersed tunnel under siltation load according to claim 3 is characterized in that: In S200, the calculation expression of the change of foundation settlement over time is obtained by combining the compression modulus, drainage distance, consolidation coefficient and cycle period of the foundation soil layer with the Taylor expansion, including: The consolidation coefficient c of the foundation v Considered as constant, the Terzaghi one-dimensional consolidation theory differential equation is introduced: Among them, c v , z, and u are the consolidation coefficient of the foundation, soil depth, and excess pore water pressure, respectively; f(t) is the load loading rate; Based on the orthogonal relationship of trigonometric functions and the inverse Laplace transform, and referring to the analytical solution of one-dimensional nonlinear consolidation of soil under continuous drainage boundary conditions, the foundation settlement S(t) at time t is calculated using the following formula: Where A=H / E S , B=2 / M; H is the drainage distance; E S is the compression modulus of the foundation; M = (2a-1)π / 2, a is a positive integer; N is the number of complete load cycles; T m1 (t), T m2 (t) is the time function to be calculated, m is the index of the summation; T q is the load cycle period; i, j are the accumulated indexes; βT q The adjustment factor for the time interval is used to scale the time offset of the accumulated items.

5. The method for calculating the settlement of an immersed tunnel under siltation load according to claim 4, characterized in that: In S300, the calculation method for determining the deformation of the pipe segment under different desilting frequencies based on the bending moment expression and the shear force expression of the Timoshenko beam model includes: Determine the cross-sectional rotation angle of the beam based on the deflection and shear strain of the beam, and determine the bending moment of the Timoshenko beam model that varies with position based on the cross-sectional rotation angle, elastic modulus, and moment of inertia of the beam; Determine the shear strain of the beam based on the deflection, cross-section rotation angle, and shear coefficient of the beam, and determine the position-dependent shear force of the Timoshenko beam model based on the shear strain, shear modulus, and effective area of ​​the beam; The deflection of the immersed tunnel is obtained based on the bending moment and shear force of the Timoshenko beam model.

6. The method for calculating the settlement of an immersed tunnel under siltation load according to claim 5, characterized in that: The deflection of the immersed tunnel is calculated using the following formula: Where s is the deflection of the immersed tunnel, T k is the prestress generated during the construction of the immersed tube tunnel; EI and GA are the bending stiffness and shear stiffness of the tube segment, respectively; K is the curvature of the neutral axis; ds / dx is the rotation angle of the neutral axis, i.e., θ. For the turning angle, is the cross-sectional shear angle caused by shear deformation, i.e., γ, f s is the non-uniform distribution coefficient of cross-sectional shear stress; α, β and γ are all intermediate quantities; P(t) is the load.

7. The method for calculating the settlement of an immersed tunnel under siltation load according to claim 6, characterized in that: The expression of the load is: P(t) = q(t)·B; Where q(t) is the sedimentation load, B is the transverse width of the pipe segment; The expression for the deflection of the right end of the pipe segment is: Where, s0 is the initial deflection; θ0 is the initial rotation angle; M0 is the initial bending moment; Q0 is the initial shear force; The bending moment of the immersed tube tunnel is obtained based on the bending moment of the Timoshenko beam model and the deflection of the right end of the tube segment; The bending moment expression of immersed tube tunnel is: According to the relationship between bending moment and shear force, the shear force of the immersed tube tunnel is obtained; The shear force expression of immersed tube tunnel is: Among them, M(x) and Q(x) are the bending moment and shear force of the immersed tube tunnel, respectively.

8. A system for calculating the settlement of an immersed tunnel under siltation load, characterized in that: The system comprises: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method for calculating the settlement of an immersed tunnel under siltation load as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a program executable by a processor, characterized in that: The processor-executable program is configured to perform the method according to any one of claims 1 to 7 when executed by the processor.

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