含气土三轴试样制备的新方法

New Method of Preparation of Gassy Soil Specimens in Triaxial Tests

为研究含气土的力学性质,对GDS公司生产的标准应力路径三轴试验系统进行了改造。通过重新设计试样底座与管路连接系统,提出了含气土试样制备的水气置换法,可以有效地控制气体含量。由于气体以游离态均匀分布在试样内部,最大程度地模拟了含气土的真实状态。以筛选后的福建标准砂为例,制备了特定饱和度的含气土,开展了含气土常规三轴试验,与饱和砂土进行了对比,验证了含气土试样制备方法的可靠性。

In the gas hydrate mining process, the saturated marine soil will become the gassy soil due to the decomposition of the gas hydrate. In order to study the mechanical properties of the gassy soil,a GDS standard stress path triaxial testing system is upgraded by redesigning the base and the pipeline connection system. A new method for preparing gassy soil samples,named gas and liquid displacement,is proposed. With this method,the gas content can be effectively controlled. Because the gas is distributed evenly in the sample,the gassy soil’s real matter state can be simulated to the most extent. Then,a triaxial shear test of a gassy soil sample with a particular degree of saturation is carried out on the Fujian standard sand after screening. The test results are compared with the triaxial test of a saturated sand sample,and the feasibility of new method for preparing gassy soil samples is verified.