外文翻译--锚杆的力学分析及工程应用

英文原文

Rock bolt mechanical analysis and its

application to engineering

Abstract Combined with the 3D FEM, end-anchored anchorage bolts were simulated by implicit anchorage bolt element. Implicit anchorage bolt elements hide in the elements of rock mass and extremely simplify the element subdivision. The calculated value of anchorage bolt stress is larger than the measured one for the most time. we further analyzed the reciprocity of anchorage bolt and rock mass, and then deduced the analytical equations of anchorage bolt stress and rock mass deformation under elasto-plastic state. The results indicate that it is essential to revise the anchorage bolts stress by using the formulas deduced when rock mass is softened or significantly deformed. Finally, a case study indicates that the calculated results agree with those measured. Some helpful methods are offerd for more accurate simulation of the support effect and anchorage bolts real stress state.

Keywords implicit element of bolt , mechanical analysis on bolt , elasto-plastic analysis

Introduction

Load transfer mechanism and strengthening effect of anchor bolts are the two major areas of anchor theory at home and abroad [1]. Geotechnical investigators have achieved a great deal of helpful datum through numerical analysis, analog test and in-situ survey method [2,3]. Reference [4] put forward implicit bolt element method, applied it to numerical calculation of large underground engineering and has gained good effect. References [5,6] used similar method to solve idiographic problems and developed it. By using

Mindlin’s displacement solution, Reference [7] deduced the shearing force distribution along anchorage length of anchorage bolt which was pulled.

The researches above just partially emphasize on either load transfer mechanism or strengthening effect. Few band the two together to study effectively. Using the case of large underground power station, we analyze the reciprocity of end-anchored bolt and surrounding rock deformation under elastoplastic state, and get some helpful conclusions.

1 Basic analysis and simplified hypotheses

The method of implicit bolt element extremely simplifies the element subdivision of FEM, further-more simulates the support effect of rock bolts preferably. The entire process of calculability is provided in Reference [4]. The method of implicit bolt element distributes support effect averagely into surrounding rock elements. Many literatures take anchorage bolt and surrounding rock as complete com-

patible deformation. However, the local influence of rock bolt ought to be taken into