A platform, system, and method for simulating critical rock collapse of surrounding rock in underground engineering includes: four vertically arranged reaction walls defining a square reaction space, and a base mounted at a lower end opening of the wall; and a row of horizontally arranged stress loading plates at a side of each wall close to the reaction space, and a reaction beam above this space, where the reaction beam, the stress loading plate, and the base define a loading space, and the loading space is configured for placement of a surrounding rock simulation block to be tested; the stress loading plate capable of moving horizontally in a direction of the reaction wall, and the reaction beam capable of moving in a vertical direction, so as to load the surrounding rock simulation block; and the stress loading plate and the reaction beam being driven by linear motion units for movement.

Provided are a device for simulating a full-scale pile-sinking process of a static pressure pile by air bag preloading and a test method thereof. The device comprises a frame, a beam, a hydraulic jack, a model box, a model pile, a first sand layer, an undisturbed soil mass, a second sand layer, a rubber pad, a forcing air bag, a counter-force steel plate, a model box top cover, a forcing pipe, a pressure relief pipe, a steel casing and a control system. The first sand layer, the undisturbed soil mass, the second sand layer, the rubber pad, the forcing air bag and the counter-force steel plate are laid in the model box in sequence; and the steel casing passes through the model box top cover, the counter-force steel plate, the forcing air bag and the rubber pad in sequence and then reaches a bottom portion of the second sand layer.

A pile-side lateral static load device includes a jack system, a liftable jack cart, a loading jack fixing system, and a loading system. The jack system includes a jack body. The jack system is installed on the liftable jack cart through the loading jack fixing system. The loading system is installed on the loading jack fixing system, and the loading system includes counter-pressure loading systems and counter-tension loading systems. The pile-side lateral static load device has a simple structure, is convenient to install and operate, and can complete lateral loading and in-situ tests under different pile diameters, different tonnages and different precisions, so as to facilitate a simulation test of in-situ lateral loading of a pile.

A pile-side lateral static load device includes a jack system, a liftable jack cart, a loading jack fixing system, and a loading system. The jack system includes a jack body. The jack system is installed on the liftable jack cart through the loading jack fixing system. The loading system is installed on the loading jack fixing system, and the loading system includes counter-pressure loading systems and counter-tension loading systems. The pile-side lateral static load device has a simple structure, is convenient to install and operate, and can complete lateral loading and in-situ tests under different pile diameters, different tonnages and different precisions, so as to facilitate a simulation test of in-situ lateral loading of a pile.

The disclosure provides a bridge foundation scouring monitoring sensor and a monitoring data analysis method thereof. The disclosed sensor comprises a cover plate, a bottom fixing unit and several standard scouring depth monitoring units fixedly disposed between the cover plate and the bottom fixing unit. Each standard scouring depth monitoring unit comprises an optical fiber vibration string (OFVS) and a supporting frame; the two ends of the OFVS are fixedly connected with the supporting frame; a plurality of polyhedral mass blocks are evenly distributed on the OFBS from top to bottom; and a fiber Bragg grating sensor is disposed at the upper portion of OFBS. The variation of scour depth of bridge foundation induces the change of vibration frequency of the OFVS, which is measured by the fiber Bragg grating sensor. The method of calculating the scour depth from the measured vibration frequency of the OFVS is disclosed.

The disclosure provides a bridge foundation scouring monitoring sensor and a monitoring data analysis method thereof. The disclosed sensor comprises a cover plate, a bottom fixing unit and several standard scouring depth monitoring units fixedly disposed between the cover plate and the bottom fixing unit. Each standard scouring depth monitoring unit comprises an optical fiber vibration string (OFVS) and a supporting frame; the two ends of the OFVS are fixedly connected with the supporting frame; a plurality of polyhedral mass blocks are evenly distributed on the OFBS from top to bottom; and a fiber Bragg grating sensor is disposed at the upper portion of OFBS. The variation of scour depth of bridge foundation induces the change of vibration frequency of the OFVS, which is measured by the fiber Bragg grating sensor. The method of calculating the scour depth from the measured vibration frequency of the OFVS is disclosed.

Provided are a testing apparatus for a pile end settlement of a rock-socketed driven PHC tube pile and an installation method thereof. The testing apparatus comprises a PHC tube pile, two measuring tubes, a cross pile tip, a pile tip steel plate, a fixer fixed in the PHC tube pile, a perforated steel plate located at a pile top of the PHC tube pile and a jack pressed on the perforated steel plate. The two measuring tubes are symmetrically arranged, the fixer is provided with two first measuring tube outlet holes, and the two measuring tubes respectively pass through the first measuring tube outlet holes of the fixer; and the perforated steel plate is also provided with two second measuring tube outlet holes, and the two measuring tubes respectively pass through the second measuring tube outlet holes of the perforated steel plate. (FIG. 1)

Provided are a testing apparatus for a pile end settlement of a rock-socketed driven PHC tube pile and an installation method thereof. The testing apparatus comprises a PHC tube pile, two measuring tubes, a cross pile tip, a pile tip steel plate, a fixer fixed in the PHC tube pile, a perforated steel plate located at a pile top of the PHC tube pile and a jack pressed on the perforated steel plate. The two measuring tubes are symmetrically arranged, the fixer is provided with two first measuring tube outlet holes, and the two measuring tubes respectively pass through the first measuring tube outlet holes of the fixer; and the perforated steel plate is also provided with two second measuring tube outlet holes, and the two measuring tubes respectively pass through the second measuring tube outlet holes of the perforated steel plate. (FIG. 1)

A sub-slab monitor includes a housing configured to extend through a foundation such that an upper surface of the housing is in contact with an indoor air environment and a lower surface of the housing is in contact with a sub-slab environment. A pressure sensor contained within the housing is configured to measure a differential pressure between the indoor air environment and the sub-slab environment, and electronics contained within the housing include a communication circuitry for communicating differential pressure data from the pressure sensor to a computer and a battery. A system and method for sub-slab monitoring includes providing and installing one or more sub-slab monitors and uploading differential pressure data from the one or more sub-slab monitors onto a central computer.

A sub-slab monitor includes a housing configured to extend through a foundation such that an upper surface of the housing is in contact with an indoor air environment and a lower surface of the housing is in contact with a sub-slab environment. A pressure sensor contained within the housing is configured to measure a differential pressure between the indoor air environment and the sub-slab environment, and electronics contained within the housing include a communication circuitry for communicating differential pressure data from the pressure sensor to a computer and a battery. A system and method for sub-slab monitoring includes providing and installing one or more sub-slab monitors and uploading differential pressure data from the one or more sub-slab monitors onto a central computer.