Method for Determining Critical Slip Surface of Cohesive Soil Slope Based on the Principle of Simple Penetration Test

In order to propose a new method for determining the critical slip surface of the cohesive soil slope, the relational expression between the number of simple penetration and slope bearing capacity is established on the basis of studying the principle of the simple penetration test with reference to the research result concerning the number of standard penetration and bearing capacity of foundation soil. The measuring points are arranged at the slope of a certain road slope according to the actual conditions, to measure the number of simple penetration, calculate the slope bearing capacity at different depths with the relational expression, draw the curve of slope bearing capacity changing with the depth, search the points of abrupt change in slope bearing capacity to get the arc curve of abrupt change points, and then determine the critical slip surface of slope. The test results are compared with the results calculated by the finite element method (FEM) and theoretical method, to verify the feasibility and rationality of the simple penetration method. The research results show that the simple penetration method is applicable to and capable of quick and accurate determination of critical slip surface of the cohesive soil slope, thus providing a new method for analyzing the slope stability of cohesive soil.

Stability evaluation and potential failure process of rock slopes characterized by non-persistent fractures

Slope failure, which causes destructive damage and fatalities, is extremely common in mountainous areas. Therefore, the stability and potential failure of slopes must be analysed accurately. For most fractured rock slopes, the complexity and random distribution of structural fractures make the aforementioned analyses considerably challenging for engineers and geologists worldwide. This study aims to solve this problem by proposing a comprehensive approach that combines the discrete fracture network (DFN) modelling technique, the synthetic rock mass (SRM) approach, and statistical analysis. Specifically, a real fractured rock slope in Laohuding Quarry in Jixian County, China, is studied to show this comprehensive approach. DFN simulation is performed to generate non-persistent fractures in the cross section of the slope. Subsequently, the SRM approach is applied to simulate the slope model using 2D particle flow code software (PFC2D). A stability analysis is carried out based on the improved gravity increase method, emphasizing the effect of stress concentration throughout the formation of the critical slip surface. The collapse, rotation, and fragmentation of blocks and the accumulation distances are evaluated in the potential failure process of the rock slope. A total of 100 slope models generated with different DFN models are used to repeat the aforementioned analyses as a result of a high degree of variability in DFN simulation. The critical slip surface, factor of safety, and accumulation distance are selected by statistical analysis for safety assurance in slope analysis and support.