公路淤泥质地基水泥搅拌桩加固效果研究

Study on Control Effect of Cement Mixing Pile in Highway Muddy Foundation

为探索水泥搅拌桩加固淤泥质地基控制效果,依托印度龙湾1#公路淤泥质地基工程,首先分析了淤泥质土的基本物理力学特性,然后借助淤泥质土水泥固化试验,探索了水泥掺量为0.0%、2.5%、5%、7.5%、10%、12.5%和15%固化土养护7d、14d和28d时的无侧限抗剪强度、不排水抗剪强度和抵抗变形能力,并据此为水泥搅拌桩确定最佳水泥掺量;最后建立数值模型,对公路淤泥质地基采用水泥搅拌桩加固控制效果进行分析。结果表明:海相淤泥质土具有含水量高、低强度、高压缩性、渗透性差、天然地基承载力低等特点;水泥掺量达到15%时,抗剪强度与抗压强度增长了约40倍,杨氏模量E增加了约250倍;龄期与水泥固化土的强度和变形密切相关,前14d龄期内能够完成28d龄期内增长值的80%左右;公路淤泥质地基采用水泥搅拌桩加固后,路基面沉降在填筑结束后20d内基本完成,侧面验证了其加固控制效果较好。

In order to explore the control effect of cement mixing pile, the basic physical and mechanical properties of silt soil were analyzed based on the silt foundation engineering of 1 # highway in Longwan, India. Then, by cement curing test, the unconfined shear strength, undrained shear strength and resistance to deformation were observed for7 days, 14 days and28 days of 0.0%, 2.5% , 5%, 7.5%, 10%, 12.5% and 15% , and then determine the optimum cement content for the cement mixing pile. Finally, a numerical model is established to analyze the effect of cement mixing pile reinforcement on the highway silt foundation. The results show that the marine muddy soil has the characteristics of high water content, low strength, high compressibility, poor permeability and low bearing capacity of natural foundation. When the cement content reaches 15%, the shear strength and compressive strength increase by about 40, and the Young＇s modulus E increased by about 250 times. The age is closely related to the strength and deformation of the cemented soil, and about 80% of the growth value of the 28 - day period can be completed in the first 14 days. After the cement mixing pile is used, the settlement of the roadbed is basically completed within 20 days after the completion of the filling, and the reinforcement control effect is better.