This paper attempts to verify the applicability of cement-soil mixing pile (CSMP) composite in the treatment of soft soil roadbed of an expressway in Guangxi, China. Firstly, the author explored the reaction mechanism of cement hydration, and examined the carbonization reaction between cement and soft soil in Guangxi. After that, the compressive strengths of CSMPs in the local soft soil with different cement contents were compared through cement-soil ratio tests. Next, the CSMP composite was adopted to treat the soft roadbed of the expressway, the settlement of the treated roadbed was monitored and the treatment effect was evaluated in details. Finally, a 3D finite-element prediction of soft roadbed settlement was conducted on Midas, providing a reference for the design and construction of the CSMP and soft roadbed in the study area. The research results show that: the cement content of 17% and the cement-soil-water ratio of 80.6: 353: 40.3 were the optimal values for the CSMP to be used in the study area; the maximum settlement of the soft soil roadbed stood at 4.3mm in two consecutive months after the CSMP treatment, which satisfies the provisions in Chinese code on highway design; the final settlement was predicted as 34.95mm through Midas 3D finite-element calculation. The research findings shed new light on CSMP application in foundations.
composite, cement-soil mixing pile (CSMP), ratio test, composite soft soil roadbed, settlement analysis
Funding sources should be included in the form of a sentence as follows, with the funding agency written out in full, followed by the grant number in square brackets: This work was supported by the Guangxi traffic science and technology project("Research on standardization of soft soil foundation treatment technology in Guangxi highway" Grant Nos. 20140203).
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