Study on Spray-anchor Rod-mesh Support Techniques Used in Xinfeng Plaza Foundation Pit

摘要

The geological condition and environment of Xinfeng plaza in Wuhan city is very complex. The foundation pit is 8.6 meters deep, which is surrounded by houses without maintenance. The dig site is situated in soft clay, and the ground water level is higher than the engineering floor. The paper introduces the design process and the engineering plan of pivot-coating net supporting technology, and describes the anchor disposition types, parameters of grouting material and solutions to the difficulties encountered during construction. The water leakage in construction is heavy, and we solute this problem in many ways simultaneously, one is to use many waterspouts to drain water. In the slope excavating stage we reinforced the silty clay before digging it. To prevent clay under the tower crane flowing, we adopted the methods of controlling displacement and increasing anchor amount successfully. Although the task is hard and the environment is complex, reinforced slope of Xinfeng plaza's foundation pit is accomplished successfully with high quality. After evaluation, the results indicate that the horizontal displacement and subside of foundation pit are controlled in the Safety Standard requirements of Hankou, Wuhan, and the foundation pit is wholly steady. The design and construction of the reinforced slope is proved to be successful by these results. The project obtains great economic benefits. The engineering is one of the deepest foundation pits in Hankou using pivot-coating net in soft clay with high ground water level. The project passed through the quicksand and soft soil with high ground water level where the depth of foundation pit using pivot-coating net supporting technology is not more than 8m, and become the model applying the new foundation pit supporting technology.