Main Participants: WANG Xiaogang, WANG Yujie, LIN Xingchao, SUN Ping, LING Yongyu, ZHAO Yufei, DUAN Qingwei, LIU Lipeng, ZHANG Qiang, JIANG Long

The slope stability analysis method is one of the classical research problems in geotechnical mechanics. The traditional limit equilibrium method for slope stability analysis, that is statically indeterminate in force equilibrium, becomes statically determinate by introducing a number of assumptions. The introduction of these assumptions not only undermines the theoretical rigor of the method, but also challenges the applicability of such assumptions in practical engineering.

The key idea of the method system is without assumptions made and not to determine the factor of safety by solving force and torque equilibrium equations as traditional way. According to the upper and lower bound theorems of plastic mechanics, the traditional slope stability analysis, without any assumptions introduced, is converted to a mathematical optimization problem searching for the maximum and minimum safety factors. As the upper-bound and lower-bound factors of safety gradually approach the real solution, a complete and unified slope stability limit analysis method system is formed.

·   Having proposed a general method of generating a slope failure mechanism in limit state. Based on the limit analysis theory of plastic mechanics, the unified mathematical optimization model of the upper and lower bound solutions for two and three-dimensional slope stability analysis is established without introducing any assumptions. It not only provides a more rigorous theoretical basis for the slope stability analysis method, but also makes a breakthrough by extending two-dimensional analysis to three-dimensional one.  

·   Having put forward for the first time the reduced-dimension mathematical expression of medium and highly nonlinear constraint equations in the optimization model. To facilitate the convergence of the optimization model with large degree of freedom and improve the optimization efficiency and accuracy, an iterative solution method of logical judgment was proposed for complex optimization mode, making this method applicable to three-dimensional slope stability analysis.

·   Having established for the first time a two-dimensional and three-dimensional slope stability limit analysis method system by integrating the upper and lower bound methods, which approaches the real solution for the factor of safety through the upper and lower bounds and can accurately determine the calculation error, marking a new breakthrough in the field of slope stability analysis. The relevant software system with independent intellectual property right has been developed and widely used in practical engineering.

The team has developed the software system for the slope stability limit analysis with independent intellectual property rights, which has been widely applied in more than 100 agencies and utilities in water resources, hydropower, transportation, railway, construction and other sectors, bearing favorable economic and social benefits. One monograph and 34 journal papers including 24 SCI/EI papers have been published; and five invention patents including one international invention patent and four software copyrights have been obtained.

Fig. 1 General Construction Method of Slope Failure Mechanism in Limit State

Fig. 2 Optimization Calculation Model for Lower Bound Solution for Safety Factor of Slope Stability

Fig. 3 Optimization Calculation Model for Upper Bound Solution for Safety Factor of Slope Stability

Fig. 4 Reduced-dimension Mathematical Expression of Yield Criterion

Fig. 5 Test Verification through Centrifugal Simulation Experiment of Wedge