Tensile cracks at the crest of slope will attenuate the stability of slope. The aim of this paper is to investigate the computation of safety factors acting on a clay slope when the slip surface consists of tensile crack and shear surface. Based on the theory of limit equilibrium, an analytical solution for safety factors containing three types of failure mechanisms is presented. The optimal crack depth was obtained by using the principle of minimum safety factor. In the solution, effects of parameters such as crack depth, slope angle, height, cohesion, and internal friction angle on slope stability were discussed. By comparing with the results of previous studies, the rationality of the proposed approach was verified. Results show that consideration of tensile cracks lead to a significant reduction in slope stability, and the safety factor decreases by about 10% compared with the slope without cracks. The law of safety factor varying with crack depth indicates that it first decreases as the crack depth is increased and then increases as the crack depth is further increased. Through the parametric analysis, it is found that the safety factor increases with an increase in cohesion and internal friction angle but decreases with the slope angle and height increase. It is important to note that the optimal crack depth does not exceed one-third of the slope height. Moreover, a highway landslide that occurred in the road running across the Yunnan and Tibet Province was investigated to verify the practicality of the present method.
This study aims to reveal the deformation characteristics of buried pipelines and the effects of various parameters on settlement displacement using the analytical analysis method. A simplified mechanical model for the settlement displacement of buried pipelines is proposed with the theory of the Winkler model, and the sensitivity impacts of various parameters are performed by comparing them with those given by other cases. The rationality of the proposed approach is verified by a comparison with previous cases, and it also turned out that the present method performed better than the other two methods in the literature in its overall tendency of settlement displacement and error precision. The parameter analysis results of this study indicate that the maximum settlement displacement of the buried pipelines only increases linearly with the increase in ground displacement. Other parameters such as the subgrade modulus and calculated length increase to a certain threshold; the maximum settlement displacement will remain stable. However, the diameter and elastic modulus of the pipelines only have a small effect on the maximum settlement displacement of the pipelines, so they are not a sensitive factor and these effects can be ignored. In addition, an engineering example of pipeline deformation in a deep foundation pit from open-cut excavation is researched to verify the practicality of this present method.
Earthquakes are one of the main causes of bedding slope instability, and scientifically and quantitively evaluating seismic stability is of great significance for preventing landslide disasters. This study aims to assess the bedding slope stability under seismic loading and the influences of various parameters on stability using a pseudo-dynamic method. Based on the limit equilibrium theory, a general solution for the dynamic safety factor of bedding slope is proposed. The effects of parameters such as slope height, slope angle, cohesion, internal friction angle, vibration time, shear wave velocity, seismic acceleration coefficient, and amplification factor on stability are discussed in detail. To evaluate the validity of the pseudo-dynamic solution, the safety factors are compared with those given by early cases, and the results show that the safety factors calculated by the present formulation coincide better with those of previous methods. Moreover, a two-dimensional numerical solution of bedding slope based on Mohr–Coulomb’s elastic–plastic failure criterion is also performed by using the finite element procedure, and the minimum safety factor is essentially consistent with the result of the pseudo-dynamic method. It is proved that the pseudo-dynamic method is effective for bedding slope stability analyses during earthquakes, and it can overcome the limitations of the pseudo-static method.