A STABILITY ANALYSIS METHOD AND ITS APPLICATIONFOR SOIL NAILING IN EXCAVATION

A method is proposed for the stability analysis of soil-nailed support system for deep excavations,This method is based on the Fellenius method of slices with the limit tensile force in the nails being included in estimating the safety factor,Novel idea is applied to define the position of the trial slip surface by a few properly chosen geometric parameters,The calculated safety factor for different slip surfaces is found to be a single-perked function of the aforementioned geometric parameters, which facilitates an efficient search of the critical slip surface by using the optimization technique of golden section.Several engineering projects are analyzed by the proposed method,and the results are compared with those obtained by the Davis method,the modified Davis method,the french method and the kinematical method.Similarities and dissimilarities among them are discussed and judeged by engineering experience,It is concluded through these calcultions that acceptable magnitude of safety factor should lie between 1.2-1.5 for ordinary projects analyzed by the proposed method.