CN-115906403-B - Joint tunnel stability analysis numerical simulation method based on discontinuous deformation analysis

CN115906403BCN 115906403 BCN115906403 BCN 115906403BCN-115906403-B

Abstract

The invention discloses a node tunnel stability analysis numerical simulation method based on discontinuous deformation analysis, which comprises the steps of firstly modifying an original DDA (distributed data acquisition) under a C language environment based on an original DDA input program dl to obtain different node parameters by different probability density functions and generate node lines and excavation cavity boundaries, secondly, importing the node lines generated by the dl program in the step one into a dc program to realize block cutting by a system program, thirdly, compiling a total balance equation of a block system considering damping into a df program to realize block displacement solving, fourthly, drawing and calculating the overall change condition and individual deformation condition of the block system, and providing a visual interface by the dg program, wherein the method can replace the original DDA program to reflect a more complex node block system, explore the influence rule of physical and mechanical parameters of node joints and the like on tunnel surrounding rock deformation, and has the characteristics of high simulation precision and strong practicability.

Inventors

LI GANG
LIU JINSHAN
XU YANXU
WANG XINGANG
Zhao Dairui
WU XINDONG
SONG ZHANPING
ZHANG YUWEI
YUE BO
DAI JIUSHENG
ZHANG YUYIN
ZHANG DONG

Assignees

中国铁建昆仑投资集团有限公司
西安建筑科技大学

Dates

Publication Date: 20260505
Application Date: 20221017

Claims (3)

1. The method for analyzing the numerical simulation of the stability of the joint tunnel based on discontinuous deformation analysis is characterized by comprising the following steps of Modifying the original DDA under the environment of C language based on the original DDA input program dl to obtain different joint parameters by different probability density functions, generating joint lines and excavating a cavity boundary; step two, importing the joint line generated by the dl procedure in the step one into a dc procedure to realize the cutting of the block body by the system procedure: step three, the total balance equation of the block system considering damping is programmed into df program to realize block displacement solution; the step three of the process of programming the overall balance equation of the block system taking into account damping into account in the df program comprises S3.1, according to the potential energy resident value principle, utilizing the Darby principle to consider dynamic balance, and adding the damping effect into a block system; s3.2, representing viscous damping force by using time step and increment of displacement, and assembling into a damping matrix; the calculation process of the damping matrix in the step S3.2 comprises S3.21, setting potential energy variation of the whole system as follows: ; Wherein: -displacement arrays, velocity arrays, acceleration arrays of the system; -an inertial force array of the system; -mass areal density of the bulk system; -an array of damping forces of the system; -an external load array of the system; -a gravitational array of systems; -elastic strain energy of the system, C being the viscous damping coefficient; s3.22 the system has n displacement independent components ; Then, the first order variation of pi is divided into zero ; S3.23 viscous drag is expressed as an array of time-varying and displacement increments, as follows: ; The potential energy of viscous damping force is expressed as ; Wherein, the 、 Representing the time step displacement increment; representing the viscous damping coefficient; 、 Representing a matrix of time step displacement increments, delta being the time step; s3.24, performing second-order variation on the above to obtain a damping matrix as ; S3.3, adding the damping matrix in the step S3.2 into an overall balance equation, and solving and calculating; S3.4, putting the generated result into a dgdt and dtat file; And fourthly, drawing and calculating the overall change condition and the individual deformation condition of the block system, and providing a visual interface by the dg program.
2. The method for analyzing the stability of an articular tunnel based on discontinuous deformation analysis according to claim 1, wherein the modifying the original DDA comprises the steps of S1.1 in the modified procedure dl, the probability Density function of the joint length is ; Wherein, the The mean value of the negative index distribution is represented, w represents the joint length; Generating random variables subject to negative exponential distribution by sample mean estimation using a computer-generated random number sequence within (0, 1) ; Wherein Z represents a uniform random number sequence on (0, 1); S1.2 the inclination and the inclination angle of the rock joint obey normal distribution or lognormal distribution, and the probability density function is that ; Wherein the method comprises the steps of The variance of the pitch trend and the dip angle is represented, w represents the pitch length; using two computer-generated columns of uniform random numbers on (0, 1) , Then generating random variables compliant with normal distribution by using Box-Muller method ; Or is a ; S1.3, determining joint distance and length parameters according to user input parameters and defining a cavity; S1.4, putting the divided joint line result into dcdt, dtat, dlps.
3. The method for analyzing the stability of a joint tunnel according to claim 1, wherein the step of introducing the joint line into the dc program comprises the steps of S2.1, calculating all node line intersection points according to the node lines obtained through statistics of the dl program in the step one; S2.2, dividing the complete joint line into independent joint line segments by using joint line intersection points to obtain a dc program of an independent block; S2.3, inputting the divided joint line results into blck, dtat, dcps, so that the subsequent retrieval and editing are convenient.

Description

Joint tunnel stability analysis numerical simulation method based on discontinuous deformation analysis Technical Field The invention relates to the technical field of geotechnical engineering computer aided design, in particular to a node tunnel stability analysis numerical simulation method based on discontinuous deformation analysis. Background In the process of researching geotechnical engineering, due to the particularity of geotechnical engineering, the field test can obtain required data, but a great amount of manpower and material resources are consumed, and the method is very uneconomical; the stability of the tunnel is generally related to the rock strength and the rock integrity, and especially under the long-term action of the stress of the original rock, geological interfaces with different scales, such as faults, joints, weak interlayers and the like, are developed in the rock; the deformation of the joint tunnel chamber in the excavation process is often similar to or even far from the prediction of the classical continuous medium theory, the continuous medium method adopts the assumption of continuous materials, the influence of an important factor of a discontinuous interface in a rock mass is ignored, so that the continuous medium mechanical method is difficult to adapt to the stability analysis of a joint rock mass tunnel, the discontinuous medium of an engineering rock mass is a relatively adaptive numerical analysis method generally comprising a discrete element method, a discontinuous deformation analysis method and the like, and the discontinuous deformation analysis method can reflect a plurality of behavior characteristics of the discrete medium and can well simulate the discontinuous characteristics of the deformation of the object. The block units in the discontinuous deformation analysis method can be contacted with each other to form an interactive integral system, and can also be separated from each other to independently move, so that the characteristics of the discrete medium can be simulated and solved; The DDA program was developed by doctor Dan Genhua of the chinese world by using the C language, and although the discontinuous deformation analysis method adopted by the DDA program is very suitable for geotechnical engineering numerical simulation analysis, the original DDA program is difficult to be qualified along with the gradual complexity of research objects and problems, and improvement on actual engineering is needed. Disclosure of Invention Aiming at the problems, the invention aims to provide a discontinuous deformation analysis-based node tunnel stability analysis numerical simulation method, which can replace an original DDA program, reflect a complex node block system, explore the influence rule of physical and mechanical parameters of the node and the like on tunnel surrounding rock deformation, and has the characteristics of high simulation precision and strong practicability. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The method for analyzing the numerical simulation of the stability of the joint tunnel based on discontinuous deformation analysis comprises the following steps of Modifying the original DDA under the environment of C language based on the original DDA input program dl to obtain different joint parameters by different probability density functions, generating joint lines and excavating a cavity boundary; step two, importing the joint line generated by the dl procedure in the step one into a dc procedure to realize the cutting of the block body by the system procedure: step three, the total balance equation of the block system considering damping is programmed into df program to realize block displacement solution; the step three of the process of programming the overall balance equation of the block system taking into account damping into account in the df program comprises S3.1, according to the potential energy resident value principle, utilizing the Darby principle to consider dynamic balance, and adding the damping effect into a block system; s3.2, representing viscous damping force by using time step and increment of displacement, and assembling into a damping matrix; the calculation process of the damping matrix in the step S3.2 comprises S3.21, setting potential energy variation of the whole system as follows: Wherein: -displacement arrays, velocity arrays, acceleration arrays of the system; -an inertial force array of the system; -mass areal density of the bulk system; -an array of damping forces of the system; -an external load array of the system; -a gravitational array of systems; -elastic strain energy of the system, C being the viscous damping coefficient; s3.22 the system has n displacement independent components Then, the first order variation of pi is divided into zero S3.23 viscous drag is expressed as an array of time-varying and displacement increments, as follows