Calculation Theory of Counterweight Double-Row Pile Support for Deep Foundation Pit in Reclamation Area and Influence Analysis of Core Pile Parameters

The theoretical calculation of a counterweight double-row pile supporting structure is deduced and studied in this paper. The derived calculation method is applied to a Midas GTS NX simulation calculation. A case study of a deep foundation pit project in Shenzhen City is used to verify and analyze the simulation results and the field monitoring results. On this basis, the influence law of deformation parameters such as the row distance, pile diameter of back-row piles and load of the pit top on the pile of a double-row pile is further discussed. The results show that both the front- and back-row piles of counterweight double-row piles are overturning deformation, and the characteristics of the horizontal displacement are basically the same. The maximum value of the horizontal displacement of the pile is at the top and the minimum value is at the bottom. With the increase in the row distance and pile diameter, the horizontal displacement of the pile becomes smaller, and the change in the pile horizontal displacement under a top load is contrary to that. Moreover, the change in the row distance has a great influence on the horizontal displacement of the pile, followed by the load of the pit top, and the pile diameter of the back-row piles has the least influence. Due to the connection effect of the horizontal plate of the counterweight platform, the whole supporting structure is in the form of a hyperstatic structure. The back-row piles can withstand most of the lateral earth pressure, which effectively reduces the deformation of the front pile and improves the overall stiffness of the supporting structure, which is conducive to the excavation stability of the deep foundation pit. Therefore, its extensive use in the Linhai soft soil project can not only effectively reduce the number of internal supports and achieve the purpose of cost saving but also increase the construction face, which is beneficial to the development of dry construction organization and management, in line with the construction concept of green environmental protection and sustainable development advocated at present.