Method for jointly testing horizontal displacement of pile head and stress of pile body of preformed pile

The invention belongs to the technical field of in-situ tests of civil engineering, and relates to a method for jointly testing the horizontal displacement of a pile head and the stress of a pile body of a preformed pile. First, self-compensating fiber grating strain sensor strings are placed in a to-be-tested pile and are sealed by using structural adhesives, after two days of maintenance, a spherical hinged support, a load sensor, a jack and a steel plate cushion block are put in sequence between the to-be-tested pile and an engineering pile, and then first perforated angle steel and second perforated angle steel are fixed; afterwards, a first datum line beam and a second datum line beam are put up, first dial indicators and second dial indicators are mounted respectively, the self-compensating fiber grating strain sensor strings are connected with a fiber grating sensor demodulation instrument, the load sensor is connected with a load sensor display instrument; after the mounting is completed, a load test is carried out on the to-be-tested pile, and corresponding displacement and strain change values are recorded. The method for jointly testing the horizontal displacement of the pile head and the stress of the pile body of the preformed pile is simple in process, convenient to operate, low in cost, high in testing precision and high in operability; obtained numerical results are direct, high in precision and small in error.