Research On The Deep Excavation Construction Technology And Its Influence On The Stability Of Subgrade

When the trench is excavated beside the existing road,necessary support measures should be taken to protect the subgrade slope.At present,most of the protection measures are mainly supported by support,such as steel sheet pile support.However,due to the increase of digging depth,the increase of the self weight of the slope and the occurrence of the seepage of the roadbed,it is not clear whether the conventional steel sheet pile supporting measures can play a proper role,especially when the supporting technology is not ideal.To ensure the safety of construction and the stability of the subgrade slope,it is necessary to combine the progress of the project with the theoretical analysis and field observation to optimize the steel sheet pile supporting process.Firstly,this paper uses the finite element software ABAQUS to simulate three conditions: excavation without support,excavation with steel sheet pile support,excavation with steel sheet pile internal and support,founding that the effect of third condition is obvious.When the roadbed is excavated near an existing road,the deformation of the typical position of the existing subgrade should be taken as the control condition.Considering the space of internal support,depth of steel sheet pile and excavation position's effect on the vertical displacement of slope,we conclude that the fisrt and third factors has significant impact.The optimization method of supporting process for deep excavation beside an existing road is proposed.Secondly,according to the actual situation,this paper makes the foundation pit excavation support scheme and carries on the comparison.The foundation pit support scheme confirms that the rain and sewage pipes are laid by the same groove,and the steel sheet piles are supported.At the same time,based on the foundation pit support calculation theory,the stability of the support structure is checked.It is found that the main problems of the foundation pit are due to the weak foundation.Then a series of key technical points are put forward for the construction.Finally,on-site monitoring of the project is carried out to investigate the engineering influence on existing roads.It is found that the steel plate support plays a stabilizing role on the displacement of the inner and surface of the roadbed and slope.