Study on Mechanical Properties and Damage Evolution Law of Secondary Destruction Induced by Simultaneous Unloading after the Peak of the Curve of Sandstone

Figure 3

Synchronous unloading mechanical experiment device and acoustic acquisition device. a: oil source; b: axis, enclosure, pore water loading pump; c: monitoring and control panel; d: computer acquisition control system (d-1: control system display and d-2: the host of the control system); e: base lift pump; f: base (f-1: axial sensor and f-2: ring sensor); g: power; h: acoustic emission host; i: acoustic emission display system; j: pressure pump for confining pressure room; k: rock sample.