Bài học xử lý sự cố cát chảy hố móng sâu bằng cọc xi măng đất

Abstract

Because of fast construction progress and lower cost than the diaphragm wall, soldier pile walls are commonly used in deep excavation. However, when designing and constructing soldier pile walls, tightness between the piles is not assured, the permeate flows the outside soil into the excavation, causing subsidence, cracking adjacent buildings, shifting the wall. This paper presents the results of troubleshooting analysis for an excavation project using the form of soldier pile wall, without waterproofing membrane, under soft ground conditions and high underwater level. Using soil cement columnms at the junction of bored piles to waterproof and reinforce the weak soil inside the foundation pit to avoid push-up. The displacement and internal force of the soldier pile wall was analyzed by using FRWS7.2 and Midas NX software to consider the effect of passive earth pressure by compression-springs theory. The results of the design and construction calculations show that the proposed solution handles infiltration and push up thoroughly, ensuring the safety of excavation construction and adjacent buildings. Thanks to those findings, the paper propose that foundation pits supported by soldier pile walls in urban areas have to consider waterproofing items from the design stage to ensure the safety of the excavation itself and adjacent buildings.