Leakage characteristics of existing underground structure of Beijing subway
To minimize the influences of the leakage defects on subway operation safety and service quality,this article proposes the classification and gradation standards of the leakage defects.At the same time,on the basis of on-site monitoring data,the spatial and temporal distribution characteristics of the leakage defects of the existing underground structure of Beijing subway were revealed.The influences of the groundwater depth,soil condition,construction method and service time on the leakage defects were also clarified.The results indicate that the leakage defects can be classified into ten leakage types,four influence grades and five leakage grades.The crack leakage,D grades and drip leakage are the main leakage types,influence grades and leakage grades of the leakage defects,respectively.The number of leakage points has the characteristic of"less in spring and autumn,more in summer and winter",and July,August and December are the high incidence periods of the leakage defects.The entrance and exit channel and the track area of the station,the crown and the side walls of the tunnel are the four areas with the highest leakage risk.The number of leakage points increases significantly with the decrease of the groundwater depth,and increases first and then decreases with the increase of the service time.Most of the leakage points occur in the sandy gravel ground and the underground structure using the mining method.
NETL
NSTL
万方数据
