碎石桩处理软土地基临界填筑高度的研究

目前计算碎石桩处理软土地基临界填筑高度的方法并不完善,没有考虑软基经碎石桩处理后复合地基强度的增加和地基排水固结能力的提高,基于此,依据固结理论,引入碎石桩复合地基固结计算的简化方法,修正按变形控制的临界填筑高度计算公式;并结合四川省遂-资高速公路软基变形监测数据,得出软基厚度在6.5~11.0 m范围内,观测所得的临界填筑高度为4.5~6.5 m,该观测值与修正公式计算值差异性不显著,证实所推导的解析式是切实可行的;在此基础上,初步探讨影响路堤临界填筑高度变化的因素,得出软基厚度、桩间距对其影响较为明显。

Research on critical placement height of gravel column reinforced soft soil foundations

Calculation methods for the critical placement height of gravel column reinforced soft soil foundations are not perfect at present. The traditional calculation methods do not take the improvement of composite foundation''s strength and the enhancement of foundation''s drainage consolidation ability into account. Based on the consolidation theory, the simplified method of consolidation calculation of gravel column composite foundation is introduced, and it modifies the formula of the critical placement height according to the deformation control. Analyzing the settlement deformation observation data of the soft ground distributed along the Suining-Ziyang expressway in Sichuan province, results show that the thickness of clay in the study area is within 6.5-11 m and the observation value of critical placement height ranges from 4.5 to 6.5 m. The difference between observation values and calculation values with modified formula is ±(0.1-0.4)m. It verifies that the formula deduced in this paper is applicable. Based on these, the factors influencing the critical placement height were discussed and it was found that the thickness of soft soil and the column spacing have more obvious influences on the critical placement height than other factors.