AUTHOR=Wu Changjiang , Yu Jun , Cao Xiaojian , Shen Wuqin 

TITLE=Study on Design Method of Pile Wall Combination Structure in a Deep Foundation Pit Considering Deformation Induced by Excavation

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2022.837950

DOI=10.3389/feart.2022.837950

ISSN=2296-6463

ABSTRACT=The technology of pile wall combination in deep foundation pit takes 
advantage of the large stiffness of retaining pile together with basement wall to resist 
soil and water pressure. As a part of basement wall, the existence of retaining pile can 
reduce the thickness of basement wall. However, the current design theory of pile wall 
combination in deep foundation pit doesn’t consider the influence of deformation 
induced by excavation and the interaction mechanism between the retaining pile and 
basement wall. Therefore, a composite structure model of elastic subgrade beam 
associated with continuous beam is proposed, and elastic spring is introduced to 
simulate the interaction between pile and basement wall. The finite difference equation 
and calculation method are established to figure out the internal force and displacement 
of pile wall combination structure. Compared to the results of field monitoring and 
FEM by the commercial software, this analytical method is proved to be able to 
accurately study the internal force and deformation of retaining pile during the 
excavation stage. Based on the above results, further investigation is carried on the
interaction between pile and basement wall during the construction and normal service 
stage of basement structure. It is concluded that the existence of basement wall can 
reduce the lateral displacement on the top of retaining pile caused by removal of strut
and affect the bending moment of upper part of retaining pile among the depth of 
basement wall, with almost no influence on the part below the bottom of pit. The 
bending moment of basement wall is closely related to the deformation of retaining pile 
and changes with the working condition. In addition, further factor sensitivity analysis 
shows that pile-wall relative stiffness ratio and stiffness of horizontal beam and slab of
basement make significant influence on the interaction between pile and basement wall.