基于沉降控制的管廊基坑肥槽回填土参数研究

Study on Parameters of Trough Backfill Soil of Foundation Pit of Utility Tunnel Based on Settlement Control

针对北京大兴新机场综合管廊10+888.5—11+074.0里程断面,采川下层三七灰土、上层优质黏土的回填方案,考虑三七灰土的强度折减系数以及优质黏土压实度的影响,分析了不同回填方案的路面沉降特征,提出了基于沉降控制的管廊基坑肥槽回填土的参数控制曲线。研究结果表明,压实度越小导致路面的沉降越大,压实度到达90%时进一步增大压实度,对道路沉降和坡率无明显影响;三七灰土的折减系数越大,道路沉降和坡率越大,对道路的沉降影响较小。

The backfill scheme,which the lower-layer is 3:7 lime soil and the upper-layer is high-quality clay,is adopted in the 10+888.511+074.0 mile section of utility gallery of Beijing Daxing International Airport.Considering the influence of the strength reduction coefficient of 3:7 lime soil and the compaction degree of high-quality clay.The settlement characteristics of pavement under different backfill schemes are analyzed.Based on the settlement control,a parameter control curve for tlie trough backfill of pipe gallery foundation pit is proposed.The research results show that the smaller the degree of compaction,the greater the settlement of the pavement.When the degree of compaction reaches 90%,further increase of the compaction will not have a significant impact on the road settlement and slope;The greater the reduction factor the 3:7 lime soil is,the greater the road subsidence and slope is and less influence on the road subsidence.