Device and method for monitoring displacement deformation of sliding surface of landslip

The invention discloses a device and a method for monitoring displacement deformation of a sliding surface of a landslip. The device comprises a slope measuring pipe positioned under the ground and more than one obliquity angle sensor positioned inside the slope measuring pipe; and the device also comprises a large-deformation measurement system which corresponds to each obliquity angle sensor one by one; the large-deformation measurement system comprises a steel wire rope, a pulley, a coding sensor and a counter weight, wherein one end of the steel wire rope and the corresponding obliquity angle sensor are positioned at the same depth measuring position; the steel wire rope is wound around the pulley on a bracket; the other end of the steel wire rope is connected with the counter weight; and the coding sensor is fixed at the center of the pulley. Aiming at the defects of the conventional landslip drilling for measuring the slope displacement, the invention provides automatic monitoring equipment which is relatively low in construction cost and can monitor and describe the whole process of the sliding surface of the landslip from deformation to destabilization, and the measurement requirement can be met due to the measurement accuracy.