Study On The Protection Technology Of Buildings Along Subway Tunnel In The Water-rich Gravelly Sand

With the expanding scale subway construction, building an increasingly broad area, often need to loose, saturated, very poor self-stability of gravelly sand in the construction of underground engineering. Particularly under the unique geological conditions in Qingdao, tunnel excavation in its formation can easily cause gushing, Chung sand, landslides and other projects accident, so the shallow buried tunnel through saturated sand gravel dimensional seepage- stress coupling analysis and grouting support their research is very important.The project reference relevant literature at home and abroad, based on the unique combination of Qingdao "soft down hard" geological conditions, Qingdao Metro Line Creek river crossing tunnel of water-saturated sand gravel engineering study for a water-rich gravel the key technical issues section of construction sand, using theoretical analysis, numerical simulation method of construction method to optimize the design. Get the main conclusions are as follows:(1) Qingdao river gravel river sand interval of relatively dense humidity is saturated, the soil belongs to the compression of the soil, for all the sand in the river gravel river sections of the tunnel excavation zone, the soil conditions extremely unfavorable for excavation.(2) in the lot of poor geological conditions of the tunnel side wear pier(or other structures), there is a mutual influence between the piers and the tunnel. Due to the pier near the disturbance of soil is too large, the tunnel excavation will cause secondary soil "activated", thus affecting the construction of the tunnel. The soil is too large deformation will also affect the safety and proper operation of the pier. When the tunnel away from the piers, less affected by the tunnel excavation; when the tunnel near the piers, which affected greatly. When the tunnel through the side piers, jet grouting pile reinforcement measures can play an effective role. Churning Pile can play a role in retaining wall between the tunnel and the pier, effectively reducing the influence of the two, effectively control the settlement and lateral deformation of the pier, surface deformation, tunnel vault settlement and lateral deformation, in order to ensure the safety and tunnel structure piers.(3) For the construction of the saturated gravel beneath the subway tunnel construction sand, the importance of controlling surface subsidence is particularly prominent. Available Forepoling beam effects and the role of rock grouting reinforcement, the control excavation in front of square Soft Rock, blocked the tunnel vault broken rock caving, rock increased strength and integrity, improve Wai rock shear capacity. Grouting reinforcement zone established around the tunnel, and will be set to the beam pipe roof unit reflects its beam effects. Injecting + bassoon studio full-face pre-construction process enables significantly reduce the surrounding rock deformation, reduced as compared with the absence of an advance guard of surrounding rock displacement of more than 80%, and full of self-stability of surrounding rock, country rock reduce internal forces and stress on the supporting structure.This project through theoretical analysis, test and numerical simulation to analyze the conclusions can provide some reference for future Qingdao subway tunnel design and construction of similar projects.