作用在岩体裂隙网络中的渗透力分析

ANALYSIS OF SEEPAGE FORCES EXERTED ON FRACTURE NETWORK OF ROCK MASS

从岩体裂隙网络渗流的特点出发 ,以单裂隙渗透力分析为基础 ,分析了二维及三维情况下岩体裂隙网络渗流对岩体裂隙壁施加的两种作用力 :垂直于裂隙壁使裂隙产生扩容的法向渗透静水压力以及平行于裂隙壁和裂隙水流方向一致的切向动水压力 ,推导出二维及三维情况下裂隙单元因这两种作用力而产生的等效结点力 ,并应用算例定量分析了岩体裂隙网络渗透静水压力和动水压力共同作用对岩体应力的影响 ,结果显示 :(a)渗透力作用下裂隙上部岩体压应力减小 ,而裂隙下部岩体压应力增大 ,最大压应力增大 10 .5 3% ;(b)渗透力作用下裂隙岩体拉应力增大 ,最大拉应力增大 9.0 9% ;(c)裂隙渗透力使岩体剪应力增大 ,最大值达 2 3.75 %。

Based on the characteristics of seepage in fracture network of rock mass, two forces the normal seepage pressure and the tangent force applied to the fracture walls are studied. The equivalent node forces of joint element are deduced under the two dimensional and three dimensional conditions. An example shows the effect of seepage in fracture network on the stress of rock mass. It comes to the conclusions that seepage forces in fracture network of rock mass decrease the compressive stress of rock mass above the fractures and increase the compressive stress of rock mass below the fractures (10.53%). The forces increase the tensile stress of rock mass (9.09%), and increase the shear stress of rock mass (23.75%).