Rockmass Mechanical Tests and Its Engineering Application about Complicated Geological Conditions Gravity Anchorage Basement
GUO Xifeng1, YU Meiwan2, WANG Xinze3
1. Chongqing Branch, Changjiang River Scientific Research Institute, Chongqing 400026, China; 2. Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan, Hubei 430010, China; 3. Yunnan Construction and Investment Holding Group Co. Ltd, Kunming, Yunnan 650501, China
Abstract:Research purposes: The mechanical parameters of the rock and soil mass of the gravity anchor foundation are an important basis for the analysis (or review) of stability against sliding. In this paper, seven geologically representative foundations were selected and in-situ mechanical tests were carried out on the bottom of the gravity anchor foundation at the Jinsha River Bridge in the Tiger Leaping Gorge of Shangrila-Lijiang Expressway, to obtain mechanical parameters such as bearing capacity and friction coefficient of the base. Research conclusions: (1) The characteristic value of bearing capacity of crushed stone soil is 119 kPa and the base friction coefficient is 0.44, the characteristic value of bearing capacity of the strongly weathered phyllite is 508 kPa and the base friction coefficient is 0.35, the base friction coefficient of the cleavage dense zone in the excavation area is 0.45, which does not meet the design requirements. (2) The characteristic value of bearing capacity of the cleavage dense zone on the right side of the anchorage foundation is 719 kPa and the friction coefficient of the base is 0.95, the characteristic value of bearing capacity of the cleavage dense zone in the excavation area of the left anchor rake angle of the anchorage foundation is 720 kPa, the characteristic value of moderate weathered sandy slate bearing capacity is 1.44 MPa and the base friction coefficient is 1.22, the characteristic value of medium weathered sandy slate with phyllite is 1.44 MPa and the base friction coefficient is 0.65, and the characteristic value of strong weathered sandy slate with phyllite 719 kPa, which all meet the design requirements. (3) For the foundations of the crushed soil with the stone mass and the strongly weathered sandy slate with phyllite that does not meet the design requirements, the measures such as excavation and replacement of concrete, consolidation grouting, are used for reinforcement, and then the anti-slip stability factors of gravity anchors are reviewed. (4) The research results can provide reference for the safe and stable operation of gravity anchorage under complex geological conditions.
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