This device is designed to derive the resistance value when plastic manhole is buried underground and exposed to the pressure of underground water. JJRBT-1 series buckling resistance tester is used to simulate the conditions when manhole is buried underground and check its resistance to the force of underground water. Seal and vaccumize the sample between 200C~250C, keep the internal negative pressure stable for more than 1000h, measure the deformation of the slow channel side and bottom, then extrapolate the deformation occurred after 50 years by the least square method.

This device is designed to derive the resistance value when plastic manhole is buried underground and exposed to the pressure of underground water. JJRBT-1 series buckling resistance tester is used to simulate the conditions when manhole is buried underground and check its resistance to the force of underground water. Seal and vaccumize the sample between 200C~250C, keep the internal negative pressure stable for more than 1000h, measure the deformation of the slow channel side and bottom, then extrapolate the deformation occurred after 50 years by the least square method.