Devices used in laboratories to measure horizontal displacement of soil around a foundation to be treated by vacuum preloading, and measurement methods

A device used in laboratories to measure horizontal displacement of soil around a region to be treated by vacuum preloading, comprising:

• a box with a top surface, a bottom surface and a peripheral side surface filled with soil, the soil being divided into a central soil region to be treated by vacuum preloading and a peripheral soil region surrounding the central soil region;
• a vertical drainage board and a vacuum pumping tube being buried within the soil in the central soil region, a lower end of the vacuum pumping tube being connected to the vertical drainage board and an upper end thereof being connected to a vacuum pump;
• a sealing membrane above a top soil surface of the central soil region;
• a loading device above the sealing membrane to assist drainage;
• transverse tubes horizontally inserted into and fixed relative to the peripheral side surface of the box, a part of the transverse tubes being in the peripheral soil region;
• an annular sensing source which moves with the soil of the peripheral soil region and which is movable along the transverse tubes and is sleeved on the transverse tubes, wherein a foot is extended obliquely and outwardly from the annular sensing source, by which the soil of the peripheral soil region drives the annular sensing source to move when the soil of the peripheral soil region moves due to the vacuum preloading of the central soil region;
• and;
• a position sensing instrument with a sensing head, wherein the sensing head is adapted to be inserted into the transverse tube from outside of the box, so that when the sensing head reaches position of the annular sensing source along the transverse tubes, an alarm signal is sent, and in this way, different positions of the annular sensing source along the transverse tubes at different moments of time are determined and horizontal displacement of the soil in the peripheral soil region is calculated.