坝基软弱破碎地质体是影响大坝安全的关键因素之一，其岩体力学参数的合理确定是大坝工程稳定分析与安全评价的基础。为合理确定向家坝水电工程左岸坝基挤压破碎带的变形模量，进行了室内MTS变形模量试验、现场小型承压板和大型承压板试验研究。3种试验方法得到的破碎带岩体变形模量基本都小于1.0 GPa，有盖层承压板试验条件下的破碎岩体变形模量测试值远大于无盖层岩体影响情况下的试验成果。研究成果表明，不同试验方法反映了左岸坝基破碎带岩体的不同受力状态，其变形模量也呈现一定差异性。在分析挤压破碎带变形模量试验值差异性的原因基础上，提出了左岸坝基破碎带岩体变形模量的建议值。

The weak geologic body existing in the dam foundation is one of the key factors influencing the safety of the dam. The determination of reasonable mechanical value for the weak rock mass is the base for the stability analysis and evaluation of safety. To reasonably determine the deformation modulus of the broken rock mass distributing in the dam foundation at the left bank of Xiangjiaba hydropower station, experiments such as MTS 3-axial servo test, in-situ conventional bearing plate test and large-scale bearing plate test are performed. The values of deformation modulus of the broken rock mass obtained by the above mentioned experiment methods are less than 1.0 GPa. The measured values of deformation modulus of the broken rock mass with covered rock layer are greater than the experimented results without overlying rock mass. It indicates that the experiment values of deformation modulus obtained by different experiment methods are different from each other due to difference of stress status during experiment process. Based on analyzing of the intrinsic reasons leading to the difference of the tested deformation modulus, and considering of the actual force state of broken rock mass in the dam foundation, a reasonable value of deformation modulus is proposed.