Device and method for preparing solidified cohesionless soil specimen for triaxial test

A device for preparing a solidified cohesionless soil specimen for a triaxial test, comprising:

• a first vessel configured to accommodate a grout;
• a first peristaltic pump;
• a grouting pipe;
• a first branch pipe;
• a second branch pipe;
• a third branch pipe;
• a flow control valve;
• a first electrode rod;
• a direct-current (DC) power supply;
• a first glass stopper;
• a polymethyl methacrylate (PMMA) pipe;
• a circumferential grouting cylinder;
• a plurality of grouting holes;
• a first hoop;
• a second hoop;
• a return pipe;
• a second rubber tube;
• a second glass stopper;
• a cotton filter;
• a second electrode rod;
• a liquid outlet pipe;
• a first rubber tube;
• a first water-stop clamp;
• a second water-stop clamp;
• a second vessel for collecting an exudate;
• a second peristaltic pump;
• and
• a circumferential space;
• wherein, the first vessel is used to store the grout;
• the PMMA pipe is of a two-piece structure;
• the first hoop is sleevedly provided on an outer side wall of the PMMA pipe;
• and both of two ends of the PMMA pipe are open;
• a top opening of the PMMA pipe is provided with a first glass stopper, and a bottom opening of the PMMA pipe is provided with a second glass stopper;
• the circumferential grouting cylinder has a two-piece structure;
• the second hoop is sleevedly provided on an outer side wall of the circumferential grouting cylinder;
• the plurality of grouting holes are evenly provided on a side wall of the circumferential grouting cylinder;
• the circumferential grouting cylinder is arranged in the PMMA pipe, and the circumferential grouting cylinder and the PMMA pipe are arranged coaxially;
• the first glass stopper abuts against a top end of the circumferential grouting cylinder, and the second glass stopper abuts against a bottom end of the circumferential grouting cylinder;
• the circumferential space is formed between the circumferential grouting cylinder and the PMMA pipe, and a soil specimen to be solidified is prepared into the solidified cohesionless soil specimen in the circumferential grouting cylinder;
• a first end of the grouting pipe is connected to the first vessel, and a second end of the grouting pipe is provided with the first branch pipe, the second branch pipe, and the third branch pipe;
• the first branch pipe and the third branch pipe pass through the first glass stopper to partially extend into the circumferential space;
• the second branch pipe passes through the first glass stopper to be inserted into the soil specimen to be solidified in the circumferential grouting cylinder;
• the first peristaltic pump is arranged at the first end of the grouting pipe;
• the first peristaltic pump is configured to drive the grout in the first vessel to pass through the first end of the grouting pipe, and the first branch pipe and the third branch pipe at the second end of the grouting pipe in sequence to be injected into the soil specimen to be solidified in the circumferential space, and then to be injected into the soil specimen to be solidified in the circumferential grouting cylinder through the plurality of grouting holes;
• and the first peristaltic pump is also configured to drive the grout in the first vessel to pass through the first end of the grouting pipe, and the second branch pipe arranged at the second end of the grouting pipe in sequence to be injected into the soil specimen to be solidified in the circumferential grouting cylinder;
• the second electrode rod passes through the second glass stopper facing the soil specimen to be solidified is provided with the cotton filter;
• one end of the liquid outlet pipe passes through the second glass stopper to extend to a bottom of the cotton filter, and the other end of the liquid outlet pipe is arranged near an flow inlet of the second vessel;
• the exudate exuding from the circumferential grouting cylinder is configured to flow through the liquid outlet pipe and the inlet of the second vessel in sequence to be injected into the second vessel;
• one end of the return pipe extends into the circumferential space through the second glass stopper, and the other end of the return pipe is arranged near an inlet of the first vessel;
• the second peristaltic pump is configured to drive the grout in the circumferential space to return to the first vessel through the return pipe;
• one end of the first electrode rod extends into the soil specimen to be solidified in the circumferential grouting cylinder through the first glass stopper, and the other end of the first electrode rod is connected to a positive electrode of the DC power supply;
• an end of the second electrode rod away from the second glass stopper is connected to a negative electrode of the DC power supply;
• a combination of the DC power supply, the second electrode rod, and the first electrode rod is configured to enable an electrochemical grouting, so as to promote a flow diffusion of the grout in the circumferential grouting cylinder;
• the first peristaltic pump and the second peristaltic pump both have an adjustable output power;
• the first rubber tube is sleevedly provided at the end of the liquid outlet pipe arranged near the inlet of the second vessel;
• the first water-stop clamp is arranged on the first rubber tube;
• the first water-stop clamp is configured to clamp or release the first rubber tube, so as to make the first rubber tube unblocked or blocked, thereby making the liquid outlet pipe unblocked or blocked;
• the second rubber tube is sleevedly provided on a middle of the return pipe, and the second water-stop clamp is arranged on the second rubber tube;
• the second water-stop clamp is configured to clamp or release the second rubber tube, so as to make the second rubber tube blocked or unblocked, thereby making the return pipe blocked or unblocked;
• and
• the flow control valve is arranged on the second branch pipe;
• the flow control valve is configured to control a flow rate of the grout in the second branch pipe, so as to achieve independent control of the flow rate of the grout in the second branch pipe.