Aiming at the localized characteristics of engineering rock mass failure, the local updating rule was established for dynamic analysis of engineering rock mass by using cellular automata technique on spatial scale and Newmark integration method on time scale, respectively. Based on a self-developed cellular automata software for engineering rockmass fracturing process(CASRock), the dynamic version, i.e. CASRock.Dyna was developed. Investigating the propagationof elastic waves in the rock mass, the stress wave propagation obtained by CASRock.Dyna was consistent with the analytical results, which verifies the feasibility of CASRock.Dyna for elastic dynamic analysis. The elasto-plastic results obtained by CASRock.Dyna were consistent with the counterparts obtained by the boundary element method, which demonstrated the ability of CASRock.Dyna for non-linear dynamic analysis. Dynamic analysis of rock mass subjected to destress blasting and blasting disturbance was conducted to explore the effect of in situ stress, heterogeneity of rock mass and dynamic parameters on failure degree and scope.

The application of 4D-LSM in rock blasting was studied. The fundamental principles of 4D-LSM in tunnel surrounding rock blasting were introduced, including system equations, non-reflective boundary conditions and rock fracturing model based on multi-body failure criterion. Aiming at the blasting of tunnel surrounding rock, 4D-LSM was used to establish the surrounding rock vibration analysis model, single hole blasting model and surrounding rock damage model under blasting. On the basis of different tunnel blasting design schemes, these models were processed through geometric simplification and boundary condition simplification to realize the quantitative analysis of the peak load velocity of the key points of the tunnel blasting surrounding rock for the given blasting scheme. Aiming at the problem of single-hole free-surface blasting, the simulation effects of DLSM and 4D-LSM were compared, and the advantages of 4D-LSM in dealing with large dynamic deformation and failure of rocks were demonstrated. The numerical modelling of surrounding rock damage zone depth under different blasting design parameters was realized by 4D-LSM. The safety classification and ranking of different blasting schemes were realized through the prediction and analysis of particle vibration velocity and damage zone depth predicted by 4D-LSM. The optimization of the tunnel rock blasting design could be realized by quantitative sensitivity analysis and ranking of blasting safety based on numerical simulation by using 4D-LSM.

Tunneling usually causes the dislocation of adjacent faults and further induces disasters such as earthquakes, but the physical mechanism is still not clear. A numerical model of near fault tunnel excavation was established by coupling mechanics of continuous media with mechanics of discrete medium. The discrete element method(DEM)was used to simulate the meso-mechanical behavior of the fault fracture zone, and the finite difference method(FDM)was used to describe the macro-dynamic characteristics of the upper and lower walls of the fault. Based on the multi-factor influence analysis, the physical mechanism of the near-fault dislocation induced by tunnel excavation was explored. The analysis results showed that the fault dislocation caused by tunnel excavation could be divided into four stages: incubation stage, acceleration stage, slowing stage and stability stage. The interaction between the fracture zone and the upper and lower walls was weak, and the rock mass deformation caused by excavation was difficult to propagate through the fracture zone to the other side. The discontinuity and disharmony of the deformation of the upper and lower walls were the main reasons for the fault dislocation. When the tunnel was located in the hanging wall, the fault displacement above the tunnel depth was positive, showing the form of positive fault, while the fault displacement below the tunnel depth was negative, showing the form of reverse fault. When the tunnel was located in the footwall, the result was opposite. The farther the tunnel was from the fault, the smaller the fault displacement caused by tunnel excavation was, and the fault displacement at different depths finally approached to 0. The increase of distance might also lead to the change of fault dislocation form below the tunnel depth. When the tunnel was located in the hanging wall, the fault displacement decreased with the increase of dip angle. When the tunnel was located at the footwall, the fault displacement above the buried depth of the tunnel increased with the increase of dip angle. The fault displacement under the buried depth of the tunnel decreased continuously. The fault displacement at the buried depth of the tunnel first decreased to 0 with the increase of dip angle, and then the dislocation form changed, and the displacement continued to increase.

To explore the dynamic fracture regularities of coal body under abrupt unloading with consideration of roof subsidence, the discretized virtual internal bond method was used to simulate the dynamic fracture process of the rock-coal-rock body under unloading condition. It was found that the dynamic fracture exhibited three-stage characteristics, namely the initial, the stable and the accelerated failure stage. With consideration of the roof subsidence, a quantitative fracture evolution function was drawn. With the initial in-situ stress increasing, the dynamic fracture in the initial and the accelerated failure stages was more violent, and the duration of the stable failure stage became shorter. The roof subsidence rate had little effect on the initial failure stage. With the roof subsidence rate increasing, the dynamic fracture in the stable and the accelerated failure stages was more violent. With the surrounding rock stiffness increasing, the duration of stable failure became longer. These findings provided valuable reference for the prediction of coal burst.

In this review, the tunnel engineering geological disasters were firstly reported, and then the simulation applications of tunnel engineering related to RFPA were summarized. The following main conclusions were that during the construction of tunnel engineering, the tunnel engineering of main geology disaster types including solid geological disasters, quasi fluid geological disasters and fluid geological disasters; the RFPA numerical methods in tunnel engineering construction related rock mechanics and failure characteristics of acquiring, under the condition of excavation of tunnel damage simulation, bedding rock tunnel excavation simulation, dynamic tunnel under the condition of failure simulation, simulation and partition of deep surrounding rock fracture under the action of seepage tunnel stability analysis were carried out in such aspects as widespread application; at present, RFPA has made important progress in the aspects of calculation accuracy, calculation scale and calculation speed, parallel computation of large-scale solution process, construction of numerical computing cloud platform and so on. It is believed that with the continuous development of technology and program, RFPA numerical calculation method will be more widely used in tunnel engineering simulation.

Based on the corrosion-damaged sewage trunk line in the southern area of Shanghai as the background, cracks in the sewage trunk line were simulated by NMM together with a newly developed SIF extraction method. The crack initiation, crack propagation process and load-bearing characteristics were simulated by fracture mechanics.The calculated displacement and stress results were in good agreement with theoretical experience and physical test results. The influence of the crack initiation length on the load-deflection curve was analyzed. Considering the random factors in the physical test, the load-deflection curve obtained by the numerical analysis agreed well with the physical test curve. After the crack occurs, the discontinuity of the displacement field on both sides of the crack was obvious. After the crack across the top steel bar, the restraint effect of the steel bar on the discontinuous displacement field and the further crack propagation was demonstrated. The analysis results showed that the manifold element had good applicability to the simulation of reinforced concrete.

The peridynamic method had great advantages in solving the problem of crack propagation in rock material due to its nonlocal characteristics. However, the method also faced problems such as zero-energy mode and boundary effects. In order to solve the above problems, the paper first proved that the non-ordinary state-based peridynamic(NOSB-PD)method was equivalent to the Galerkin weak form with nodal integral scheme. The equation of solving the deformation gradient F in NOSB-PD method was extended to a more general form, namely the peridynamic differential operator(PDDO)approximation. Since the PDDO had the same displacement approximation with the reconstruction kernel particle method(RKPM), this paper compared the difference between the two methods in the approximations of displacement derivatives in detail. The RKPM-PD coupling method with higher accuracy was proposed in the paper. Several numerical examples proved the accuracy of the new method in predicting the dynamic crack propagation in rock.

In order to study the hydraulic fracturing characteristics of water resisting rock mass with layered joints in karst tunnels, an analysis model of water resisting rock mass was established, the key factors affecting the critical hydraulic pressure of rock column was obtained through dimensional analysis, and the rock strength properties of single joint element was analyzed. With the help of continuum-discontinuum element method to observe the fracture crack and penetration process,the failure mode and critical water pressure of the water resisting rock mass with different joint inclination angles were obtained, as well as the evolution law of the rock mass fracture degree and damage degree. The numerical results showed that the failure modes of water resisting rock mass with layered jointed included bedrock failure, interlayer failure and composite failure; influenced by the weight of overlying strata, the critical water pressure of water resisting rock column had an obvious obliquity effect, which first decreased and then increased; the fracture degree and damage degree of interlayer penetrating failure were much less than that of bedrock penetrating failure.

The underground caverns of a hydropower station under construction are large in scale, with high side walls and large span.The deformation, stress evolution and plastic zone distribution characteristics of surrounding rock mass during layered excavation of underground caverns were studied by numerical simulation method, and the deformation and failure mechanism of surrounding rock mass was analyzed based on the results. Results showed that the failure of surrounding rock mass in the early excavation of the caverns was dominated generally by stress, and gradually changed to dominated by structural plane with the increase of excavation face. The numerical simulation results revealed the failure characteristics of hard rock with high in situ stress under the influence of structural plane, which could provide reference for the formulation of excavation measures and support design of caverns.

The stability of geotechnical structures such as slopes and tunnels is often quantified by safety factors. There are three standards for defining factor of safety: the ratio between resistance and driving forces; strength reduction factor and load increasing factor. Aiming at the commonly used strength reduction and load increasing factors, a novel upper bound limit analysis method based on topology optimization theory: discontinuity layout optimization(DLO)was used to study the obtained values considering different conditions. The target functions were proposed considering strength reduction and load increasing. Several numerical examples were tested, indicating the efficiency and reliability of DLO method. Meanwhile, the differences between the factors of safety of strength reduction and load increasing depend on the value itself and friction angle.

To simulate the effect of grouting to control large lateral deformation and its mechanism analysis, the discrete element pore density flow method was proposed. Through the improvement of the discrete element software MatDEM, the numerical simulation of the fluid-solid coupling process of tunnel grouting was realized. Based on the instance data of the Shanghai Tunnel Project, the discrete element analysis of tunnel grouting under sudden load was carried out. The numerical simulation of the tunnel lateral convergence value was very close to the test result. Numerical analysis showed that as the sudden load increased, the horizontal convergence of the tunnel showed a nonlinear growth trend; the pore density flow method was used to analyze the recovery effect of grouting on the transverse deformation of the tunnel. The results showed that with the sudden load and grouting as the distance increased, the influence of grouting on the recovery percentage of the tunnel lateral convergence decreased nonlinearly. This method can be further applied to the numerical analysis and mechanism research of tunnel grouting under complex conditions.

Contact detection and computation efficiency has always been the key problem of three-dimensional discontinuous deformation analysis(3D-PEDDA), which is one of the most powerful numerical methods. Contact detection suffers from low efficiency, contact indeterminacy, and the incapability to deal with concave blocks. The efficiency of the entire DDA program is also one of the most crucial bottlenecks. This paper introduced the multi-cover method and the last entrance plane method to deal with lacking of efficiency and indeterminacy of contact detection, as well as the local convex decomposition method for concave polyhedron. In addition, in order to improve the computational efficiency, 3D explicit DDA was adapted to unify data reading and writing mode, and parallelized by adding precompile instructions. In order to expand to high-performance cloud computing and supercomputers, the new 3D-PEDDA programs were all developed on Linux system, and preliminary experiments were carried out on a simple cloud virtual machine. Numerical examples verified the efficiency and accuracy of the newly developed parallel 3D-PEDDA, and it is promising that it can be easily extended to high-performance virtual machines or supercomputers to realize the analysis of large-scale projects.