压力分散型锚索设计中应考虑的几个问题

 在分析压力分散型锚索锚固机制的基础上，提出该类锚索设计中应考虑的3个问题，即单元锚固段长度的计算问题、承压板处浆体的变形问题和工后坡体变形引起钢绞线的不均匀荷载问题，认为该类锚索较拉力型锚索的锚固力有所提高，是因为浆体受压时径向的膨胀变形受到岩土体约束，岩土体越坚硬约束作用越强，锚固力提高值越多，反之则小。由此提出物理概念清楚、计算简单的单元锚固段长度计算公式。按照承压板处浆体的变形特征，提出变形量的计算公式，由此可进行浆体的变形验算。为消除工后坡体变形引起钢绞线的荷载不均匀问题，建议采用基于工后允许位移的张拉法，给出详细张拉顺序和计算公式。

SOME PROBLEMS TO BE CONSIDERED IN DESIGN FOR COMPRESSION DISPERSION-TYPE ANCHOR CABLES

On the analysis of anchoring mechanism for compression dispersion-type anchor cable，three problems that should be considered in the anchor cable design have been put forward，namely the calculation of unit anchor length，the deformation of grouting body near pressure plate and the nonuniform loads of steel strand wires caused by the rock mass deformation after slope completed. The anchorage force has been improved to compare with tension type anchor cable，because the radial expansion deformation of grouting body is restrained by the rock mass. The hard the rock mass is，the stronger the restriction is；and the more the improved anchorage force，otherwise，the smaller. A formula for calculating anchoring length，of which the physical concept is clear and calculation simple，is presented，together with the formula to determine the deformation of the grouting body near pressure plate. In order to eliminate the nonuniform loads，the anchor cable tension method is recommended，in which rock mass permitted displacement after slope completed is considered；and the detailed tension order and the calculation formulas are also given.