Development and application of multi-field coupled high-pressure triaxial apparatus for soil

The increasing severity of ground subsidence, ground fissure and other disasters caused by the excessive exploitation of deep underground resources has highlighted the pressing need for effective management. A significant contributing factor to the challenges faced is the inadequacy of existing soil mechanics experimental instruments in providing effective indicators, creating a bottleneck in comprehensively understanding the mechanisms of land subsidence. It is urgent to develop a multi-field and multi-functional soil mechanics experimental system to address this issue. Based soil mechanics theories, the existing manufacturing capabilities of triaxial apparatus and the practical demands of the test system, a set of multi-field coupled high-pressure triaxial system is developed tailored for testing deep soils (at depths of approximately 3 000 m) and soft rock. This system incorporates specialized design elements such as high-pressure chamber and horizontal deformation testing devices. In addition to the conventional triaxial tester functions, its distinctive feature encompass a horizontal deformation tracking measuring device, a water release testing device and temperature control device for the sample. This ensemble facilitates testing of horizontal and vertical deformation water release and other parameters of samples under a specified stress conditions, at constant or varying temperature ranging from −40°C–90°C. The accuracy of the tested parameters meets the requirements of relevant current specifications. The test system not only provides scientifically robust data for revealing the deformation and failure mechanism of soil subjected to extreme temperature, but also offers critical data support for major engineering projects, deep exploration and mitigation efforts related to soil deformation-induced disaster.