Abstract：
Most coastal regions in China are of muddy ground with thick mud stratum. Under such geological conditions, comprehensive pipe gallery project often encounters complex deep foundation pit construction and high quality and safety risks, while traditional construction method may cause foundation pit bottom upheaval even collapse of foundation pit. Lassen steel sheet pile and mechanically combined internal support method were adopted to successfully solve these problems through alternative bay excavation, counter pressure and support effects of concrete cushion. Meanwhile, construction period and cost were reduced.
