Clamp of elastic box of stiff true-triaxial testing system and displacement monitoring method for cuboid specimens

A clamp of elastic box of stiff true-triaxial testing system, comprising:

• six pressing plates and eight plate springs,
• wherein the six pressing plates form a hexahedral empty box structure, each surface of the hexahedral empty box structure is provided by one pressing plate, a center of the hexahedral empty box structure is used as a coordinate origin, a spatial rectangular coordinate system is established in directions perpendicular to the six surfaces, the pressing plates on two opposite surfaces of an X-axis direction are a pressing plate X-a and a pressing plate X-b, the pressing plates on two opposite surfaces of a Y-axis direction are a pressing plate Y-a and a pressing plate Y-b, and the pressing plates on two opposite surfaces of a Z-axis direction are a pressing plate Z-a and a pressing plate Z-b, and
• wherein one ends of the pressing plate X-a and the pressing plate X-b, away from the hexahedral empty box structure, are fixedly connected with two plate springs B along the Z-axis direction, and the other ends of the plate springs B are fixedly connected with the pressing plate Z-a and the pressing plate Z-b respectively;
• one end of the pressing plate Y-b, away from the hexahedral empty box structure, is fixedly connected with the two plate springs B along the Z-axis direction, and the other ends of the plate springs B are fixedly connected with the pressing plate Z-a and the pressing plate Z-b respectively;
• and the pressing plate Y-a is fixedly connected with two plate springs A along the X-axis direction, and the other ends of the plate springs A are fixedly connected with the pressing plate X-a and the pressing plates X-b respectively.