中文摘要：

为探寻共面双线断续节理岩体平面应力条件下的拉伸特性,从远场应力角度出发,基于Fazil Erdogan（1962）在任意荷载条件下共线双裂纹的应力场分布思想,采用G.C.Sih（1972）提出的最小应变能密度因子判据（S判据）,建立了远场应力与裂纹尖端附近应力场的对应关系,证明共线双裂纹在拉应力作用下自相似扩展;裂纹外侧与内侧的应力场分布形式相同,但数值偏小,且内侧裂纹先于外侧裂纹扩展;在材料性质、裂纹间距及长度已知的情况下,可反推材料破坏时的极限外力大小。

英文摘要：

In order to deduce the tension properties of intermittent jointed rock with double-line,in terms of far-field stress,this paper establishes a corresponding relationship between a far-field stress and the stress field around the crack tip based on the theory of stress distribution of two collinear cracks under any load（Erdogam,1962） and the minimum strain energy density factor criterion（Sih,1972）.Furthermore,the paper demonstrates that the two collinear cracks follow self-similar extension under tensile stress;the stress fields on the inside and outside of the crack have the same distribution with some difference in magnitude,and the inside crack extends earlier than that of the outside crack.If the material properties,the spacing and length of the cracks are known,the magnitude of external destructive force can be derived.