锚索支护传力机制与应力分布的数值模拟

采用FLAC^3D对锚索预应力在巷道围岩中形成的应力场－锚索预应力场分布特征进行了数值模拟.结果表明：在一定预应力条件下，单根锚索在其周围形成了类似“心”形的压应力分布区域，压应力在锚索尾部附近最大，锚固起始处附近次之，锚索自由段中部较小.锚索锚固段附近出现了拉应力区，但拉应力值很小；多根锚索形成的压应力区相互叠加，并连成一体，形成类似“鼓”形的整体支护结构，锚索预应力及主动支护作用扩散到大部分锚固区域.锚索预应力场分布形态与锚索长度、间距、排距、安装角度、预应力的大小及组合构件有关.

Numerical simulation on load-transfer mechanisms and stress distribution characteristics of cable bolts

A number of numerical simulation tests were carried out using the numerical analysis code FLAC3D to investigate stress distribution characteristics caused by pretensioned stress of cable bolts.The results show that when a single cable bolts install with pretensioned stress,a heart-shape compressive stress fields will be formed around the most length of cable.The highest compressive stress will locate near the collar,and the higher near the lower part of the grouted portion,and the lowest near the free portion.A tensile stress fields will also be formed by the near of the upper part of the grouted portion,but the tensile stress magnitude is very small.When many cable bolts are installed within certain spacing,compressive stress fields caused by single cables will superpose with each other and will form a drum-shape holistic supporting construction.The pretensioned stress and active support effects will diffuse to the whole anchorage rockmass.The distribution characteristics of Cable Bolts Pretensioned Stress Fields(CBPSF) are relative to cable length,numbers per row,row spacing,magnitude of pretensioned stress,and the strap.