Analysis on Leakage Disease Law of Metro Deep Foundation Pit Retaining Structure
In order to grasp the law of leakage disease of the deep foundation pit retaining structure,the general situa-tion of the Hangzhou Metro project and the engineering geological background were expounded.A statistical study was carried out based on the leakage disease data from 2015 to 2021,and the relationship between leakage and geology,geography,structure and deformation factor was analyzed.The results show that:(1)The engineering geological lay-ers ③ and ⑥ occupy the main position in the stratum lithology where the leakage disease develops,and the pore wa-ter is the main groundwater source of the leakage.(2)The lateral gradient of the adjacent rivers that supply founda-tion pit leakage is divided into rare(i≥0.117),frequent(0.022≤i＜0.117)and easy(0.006≤i＜0.022)occurrence;the 5 day cumulative rainfall is divided into low(0-25.4 mm/5d),moderate(25.4-67.1 mm/5d)and high(67.1-82.3 mm/5d)intensity,which can respectively induce grade Ⅰ-Ⅱ,Ⅲ and Ⅳ leakage.(3)The corner joints of the retaining structure of deep foundation pits are prone to leakage,and the retaining structures of grade Ⅳ diseased foundation pits with low 5 day cumulative rainfall often possess serious defects.(4)Leakage is distributed within 5 m above the excavation surface,and the shallowest critical buried depth and excavation depth,the shallowest critical excavation depth and the design depth of the foundation pit are both in an exponential relationship.The leakage is locat-ed within the range of 6.0 m above and 2.5 m below the maximum lateral deformation,and the depth of both is linear-ly positively correlated.The relationship between the leakage depth and the maximum lateral deformation/deformation depth is linearly negatively correlated in different regions,and the slopes of the fitting lines in different regions are similar.The mechanism of the development pattern of leakage diseases was discussed.A typical engineering example was selected to identify the leakage risk and verify the reliability of the law analysis.The research can provide a refer-ence for the prevention of leakage in deep foundation pit engineering in water-rich sand layer.
deep foundation pitretaining structureleakage diseasestatistical analysis
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万方数据
