中文摘要：

以钠基膨润土为充填介质,水泥砂浆为裂隙壁制作充填裂隙,采用法向压缩、侧向约束的方式,对不同宽度和不同含水率条件下膨胀性充填裂隙的本构关系进行了探讨,获得了大量应力、应变实验数据。研究表明,膨胀性充填裂隙峰前本构关系可划分为3个阶段：流变阶段、压密阶段和弹性阶段。实验开始时,充填裂隙即进入流变状态,也就是说应力基本保持不变,而应变持续增加,随着有限变形及法向应力的增加,充填裂隙整体强度增大,逐渐表现出弹性特征。根据实验数据和特征,提出倒圣维南体（inverted Saint-Venant body）力学模型,建立了膨胀性充填裂隙本构方程,并分析了其内在作用机制。

英文摘要：

Taking Na-bentonite as filling medium and cement mortar as fissure wall,the filled fractures are made.By means of normal compression and lateral restraint,the constitutive relations of filled fracture with expansive medium and under the conditions of different fracture widths and different water contents,are discussed.A large number of stress-strain data are obtained.It is shown that the fractures filled with expansive medium can be divided into three stages： rheological phase,compression phase and the elastic stage in the pre-peak.At the beginning of the experiment,the filled fracture is in the rheological state;that is to say,the stress nearly remains unchanged,but the strain continues to increase.With the finite deformation and the normal stress increase,the filled fracture overall intensity increase,and demonstrate elastic characteristics gradually.Based on the results,the mechanical model of inverted Saint-Venant body is put forward;pre-peak constitutive equation of filled fracture with expansive medium is established;and its mechanism is analyzed.