A method for constructing a large-span station by two-wing open type semi-covered excavation and semi-reverse construction, is divided into three stages of excavation. First, excavate a first-stage inner small foundation pit, then excavate a second-stage annular foundation pit within the first-stage retaining piles and outside the range of the first-stage inner small foundation pit, and finally excavate a third-stage semi-covered excavation foundation pit below the first-stage inner small foundation pit and the second-stage annular foundation pit. By setting graded retaining piles, middle upright post piles, middle top plates, local waist beams and local concrete supports in the soil-rock combination strata, so that the force transfer between the foundation pit enclosure and the station main body structures and the underlying rock layer is clear and reliable, and a stable frame structure is achieved.

A method for constructing a large-span station by two-wing open type semi-covered excavation and semi-reverse construction, is divided into three stages of excavation. First, excavate a first-stage inner small foundation pit, then excavate a second-stage annular foundation pit within the first-stage retaining piles and outside the range of the first-stage inner small foundation pit, and finally excavate a third-stage semi-covered excavation foundation pit below the first-stage inner small foundation pit and the second-stage annular foundation pit. By setting graded retaining piles, middle upright post piles, middle top plates, local waist beams and local concrete supports in the soil-rock combination strata, so that the force transfer between the foundation pit enclosure and the station main body structures and the underlying rock layer is clear and reliable, and a stable frame structure is achieved.

An end point closing wall forming device of an extrusion type underground diaphragm wall comprises a main body (1) and a vibration water spraying device. The vibration water spraying device is fixedly disposed inside the main body (1). The end point closing wall forming device of an extrusion type underground diaphragm wall further comprises a separation device. The separation device is movably sheathed on the outer side of a short edge (11) of the main body (1). Also provided is a method for operating an end point closing wall forming device of an extrusion type underground diaphragm wall.

Disclosed herein are a module, system and technique to enhance end bearing stiffness of pile/drilled shafts. In particular, methods, systems and loading modules which account for tip resistance in overall pile/shaft capacity are provided which increase the stiffness of the bearing soil. The techniques utilize a mechanical system to preload the soil under the shaft tip, thus allowing the users to confidently account for the gained resistance at an acceptable level of movement. Each shaft/pile is preloaded during construction to verify its load carrying capability.

The present application is directed to an automatic pilot valve (APV) system for foundation tooling, such as a continuous flight auger (CFA) or displacement tool structured to include a pilot tip receiving housing in communication with a cement supply in which when the pilot tip is in the retracted position while drilling operations are being performed, the pilot tip shaft blocks the flow of cement into the drilled hole. When the APV equipped CFA is being lifted out of the drilled hole, the APV pilot shaft slides outwardly simultaneously exposing one or more cement ports allowing cement to flow. The APV can include a one-piece machined, cast or forged valve housing, or manufactured by welding steel components into a multi-piece valve housing. The APV can be deployed externally by attachment to the outside of foundation or displacement tool stems or internally by installation inside of foundation or displacement tool stems.

The present application is directed to an automatic pilot valve (APV) system for foundation tooling, such as a continuous flight auger (CFA) or displacement tool structured to include a pilot tip receiving housing in communication with a cement supply in which when the pilot tip is in the retracted position while drilling operations are being performed, the pilot tip shaft blocks the flow of cement into the drilled hole. When the APV equipped CFA is being lifted out of the drilled hole, the APV pilot shaft slides outwardly simultaneously exposing one or more cement ports allowing cement to flow. The APV can include a one-piece machined, cast or forged valve housing, or manufactured by welding steel components into a multi-piece valve housing. The APV can be deployed externally by attachment to the outside of foundation or displacement tool stems or internally by installation inside of foundation or displacement tool stems.

An auger-suction type metro jet system (MJS) device for aerated and lightweight cement soil includes a multi-pipe device, an outer sleeve, an integrated device, a spiral conveyor, a reamer head, a pressure monitoring system, a mass measuring device, and a control console. The multi-pipe device integrates a backup pipe, a negative-pressure gas pipe, a hydraulic pipe, a negative-pressure water pipe, a pressure sensor wire pipe, a pressure water pipe, a backup gas pipe, a power wire pipe, and at least one grouting tremie unit. The spiral conveyor includes a shaft-type spiral conveying belt and a negative-pressure device. A construction method for foundation reinforcement construction includes: cutting soil by the reamer head; crushing gravel by a gravel crusher; transporting, by the shaft-type spiral conveying belt, a soil-water mixture to a waste liquid tank; monitoring, by the mass measuring device, a mass of the soil-water mixture discharged; and injecting equal-mass cement.

An auger-suction type metro jet system (MJS) device for aerated and lightweight cement soil includes a multi-pipe device, an outer sleeve, an integrated device, a spiral conveyor, a reamer head, a pressure monitoring system, a mass measuring device, and a control console. The multi-pipe device integrates a backup pipe, a negative-pressure gas pipe, a hydraulic pipe, a negative-pressure water pipe, a pressure sensor wire pipe, a pressure water pipe, a backup gas pipe, a power wire pipe, and at least one grouting tremie unit. The spiral conveyor includes a shaft-type spiral conveying belt and a negative-pressure device. A construction method for foundation reinforcement construction includes: cutting soil by the reamer head; crushing gravel by a gravel crusher; transporting, by the shaft-type spiral conveying belt, a soil-water mixture to a waste liquid tank; monitoring, by the mass measuring device, a mass of the soil-water mixture discharged; and injecting equal-mass cement.

Disclosed herein are a module, system and technique to enhance end bearing stiffness of pile/drilled shafts. In particular, methods, systems and loading modules which account for tip resistance in overall pile/shaft capacity are provided which increase the stiffness of the bearing soil. The techniques utilize a mechanical system to preload the soil under the shaft tip, thus allowing the users to confidently account for the gained resistance at an acceptable level of movement. Each shaft/pile is preloaded during construction to verify its load carrying capability.

A porewater pressure dissipater is disclosed. In one example, a disclosed dissipater includes aggregate; a cylindrical receptacle for receiving the aggregate; a plate having a top surface and a bottom surface and one or more openings transcending from the top surface to the bottom surface wherein the plate secures and compacts the aggregate in the cylindrical receptacle; and one or more access tubes coupled to the top surface of the plate wherein the one or more access tubes are positioned over the one or more openings thereby forming a passageway to the cylindrical receptacle. The disclosed dissipater allows piles and shafts to be embedded at the optimum depth without concerns of liquefaction.