Stability analysis method for the composite foundation embankment based on pile shear strength

In the current specification, the stability analysis of the embankment slope is calculated by combining the strength parameters of the two parts of pile and the soil into a single parameter, which will cause the slope stability and the position of the most unfavorable slip surface to deviate from the actual project. Therefore, by using the Swedish strip method and the simplified Bishop method to analyze the slope stability principle, through the separate analysis and calculation of the stability moment and sliding force distance of the anti-slide pile and the soil between the piles, a pile-soil algorithm for embankment slope stability analysis is proposed. The pile-soil division algorithm and the code method are used to analyze the stability and landslide failure characteristics of slopes with different reinforcement pile diameters, pile spacing and embankment heights. The results show that the pile-soil calculation has the largest stability coefficient calculated by the Swedish strip method, followed by the pile-soil calculation Bishop method, and the standard method has the smallest stability coefficient. The embankment slope stability coefficients based on the three methods all decrease as the slope height increases. The difference between the stability coefficients calculated by the standard method and the pile-soil algorithm shows a parabolic change that increases first and then decreases as the slope height increases. The difference between the two pile-soil separation algorithms is approximately linear. In addition, the position of the most unfavorable sliding surface of the slope obtained by the analysis of the pile-soil analysis algorithm shows a “downward” phenomenon. With the code method, the most unfavorable arc sliding surface of the slope passes through the middle of the foundation reinforcement area. However, when the height of the embankment slope is 9~15 m, the pile-soil algorithm analysis indicates that the most unfavorable arc slip surface passes the flexible pile reinforcement area and is located below the bottom of the flexible pile reinforcement area, and the slope is not yet stable.