振冲挤密加固深厚吹填珊瑚礁砂地基试验研究

Experimental Study on the Reinforcement of Deep Filled Coral Reef Sand Foundation through Vibroflotation Compaction Method

摘要:

针对沙特吉赞新建的围海造陆货物堆场的地基处理，基于珊瑚礁砂的疏浚工程特性，开展了用两种振冲挤密法加固该处不良级配疏松礁砂地基的有效性及确定其相应工艺参数的现场试验。先完成选定小区试验，后由SPT检验其效果，再分析确定最优振冲工艺并指导了大面积工程施工。通过比对场区地基加固前、后的CPT检测结果，用Iwasaki液化指数法对振后地基做进一步液化判断，同时采用极限法（基于CPT）和施莫法（基于SPT）对加固地基进行了沉降分析并对比两种计算结果，验证本试验研究所确定的加填料振冲方案与施工工艺合理性，加固后地基的承载及抗液化能力得到有效提高且完全能满足工后沉降控制要求。研究成果可供珊瑚礁海域的类似工程参考或借鉴。

Abstract:

Aiming at the foundation treatment of some new goods yards in Jazan, Saudi, this experimental study focused on the validity of reinforcing the poorly graded and loose foundation of coral reef sand through two vibroflotation compaction methods. Technique parameters were determined based on the engineering characteristics of dredged coral reef sand. First, the trial of the selected field area was completed, and the effect was verified by SPT test. The optimal vibroflotation technique was determined to guide the construction in a large area. The CPT test results were compared before and after the foundation reinforcement. A further liquefaction judgment was conducted using Iwasaki liquefaction index method. The settlement analysis on the improved foundation was conducted using limit equilibrium method (based on CPT) and Schmertmann's method (based on SPT). The results were then compared. The proposed scheme and construction technology were found to be reasonable and correct. The bearing and anti-liquefaction capacity of the reinforced foundation were improved effectively and satisfied the requirement of settlement control. The results can be used as reference for similar projects in the sea area of coral reef.