During construction of Hepingdong Bridge – Sun Palace thermal power pipeline in Northern third loop road of Beijing City

the pipeline tunnel would go through beneath a couple of single-floor houses

whose area is 23.4 m×24.5 m. Due to the shallow overburden and the saturated microfine sandy clay

which is plastic and soft plastic

the strata is very weak in resisting interruption. The traditional dewatering is limited to improve the nature of the strata. Based on calculation

it is believed that the common construction method would necessarily cause much settlement and endanger the houses. Meanwhile

as the strata are hard to stand up

safety problems may be triggered in construction. In view of these

the level long steel pipes are adopted to support soil mass and grouting in the upper half face of the tunnel is operated to prevent ground water and strengthen soil without dewatering. These two methods effectively control the settlement of ground surface and ensure the perforation of the tunnel in time and running of the houses in security.