新疆某水库坝基砂层透镜体物理力学性质试验研究

Experimental Study on Physical and Mechanical Properties of Sand Lens for a Reservoir Dam Foundation in Xinjiang

新疆某平原水库坝基分布的砂层透镜体,其物理力学参数是否满足坝基土层的设计要求,对工程建设方案设计和施工处理措施具有重要的影响。通过室内物理力学性质试验和原位标准贯入试验,研究了该坝基的砂层透镜体的物理力学性质。研究发现,该砂层透镜体为粉砂,颗粒级配良好,结构密实,属于低压缩性土;抗剪强度和地基承载力满足设计要求,但渗透系数偏大,为中等透水性砂土,远大于设计渗透系数的要求;该层为水库渗漏的主要通道,水库的防渗墙必须截断该透镜体,确保坝基和坝体的防渗符合设计要求,才能有效地解决水库的防渗问题。研究成果为坝基稳定性设计提供充分和确切的试验数据和工程参考依据。

The dam foundation of a reservoir in Xinjiang is sand lens ,whose physical and mechanical parameters are very important for the project design and construction .Based on the laboratory tests and in-situ standard penetration tests ,the physical and mechanical properties of the dam foundation’s sand lens were studied .It is found show that the sand lens is silty sand ,it has well particle size distribution and dense structure ,and it belongs to the low compressibility soil ;The shear strength and bearing capacity of the sand lens could meet the design requirements ,but its permeability coefficient is far larger than the design requirements because it belongs to the moderately permeable sand-soil ;the sand layer is the main channel of reservoir leakage ,so it must be truncated by the cutoff wall in order to ensure that the dam foundation’ s seepage control to be in accord with the needs of design and effectively solve the problem of reservoir ’s seepage control . The research results of this paper could provide the good test data and engineering reference for the stability design of dam foundation .