Research On Reinforcement Technology Of Pressure-Dispersion Ancor Cable In Slope

Pressure-dispersion anchor cable has been widely used in anchoring engineering.Compared with tension anchor cable,its mechanical mechanism is more reasonable and its anchoring performance is better.However,the anchoring mechanism of pressure dispersed anchor cable is complex,the reasonable length of unit anchoring section under different rock and soil conditions,needs to be further investigated,and the long-term prestress of anchor cable is not easy to evaluate.Based on the foundation pit(slope)project in Wuxiang new district,Nanning,this paper does research on the anchoring mechanism,reasonable spacing of bearing plates,ultimate pullout bearing capacity and long-term prestress loss of anchor cable through theoretical summary,field test and numerical simulation.The main contents and results are as follows:(1)The common theoretical solutions of the anchoring mechanism of pressure-dispersed anchor cable are summerized,the calculation model of pressure-dispersed anchor cable is established by FLAC3 D to study the stress state of its anchoring section.The differences between the four theoretical solutions and the numerical solutions are also analyzed.The stress characteristics of grouting body rock-soil body in anchoring section are studied by numerical solution of anchoring section.(2)Based on the stress distribution results of anchorage sections under different rock and soil conditions obtained by the established numerical model,the reasonable unit anchorage section lengths of soft rock,extremely soft rock,soil-like soil and clay.(3)The structure and stress characteristics of pressure-dispersion anchor cable are studied.The failure modes of pressure-dispersion anchor cable are summarized,and the theoretical ultimate uplift capacity calculation method is obtained based on the failure modes.The feasibility of this calculation method is verified by field pullout tests.At the same time,the sensitivity analysis of the factors affecting the ultimate uplift capacity of pressure-dispersed anchor cables is carried out.(4)Based on the monitoring data of the prestress of anchor cable in slope engineering,the hyperbolic method is adopted to fit and anlyze the data,and the long-term variation law of the prestress of anchor cable in this engineering is discussed.In addition,the generalized Kelvin model of creep coupling effect is used to establish the calculation model of long-term prestress loss of anchor cable,and the applicability of the model to this project is verified by comparison with monitoring data.This paper analyzes several factors influencing the long-term prestress loss,and put forward some methods for controlling the long-term prestress loss of anchor cable.