PCMW工法在基坑工程中的应用——以南京某工程为例

Application of PCMW Method in a Foundation Pit Engineering:Taking a Project in Nanjing for Example

在说明应用PCMW工法需验算的几个参数的基础上,以南京某学校地下车库基坑工程为例,对基坑工程的支护结构水平、垂直位移,深层土地水平侧向位移,支撑轴力、立柱沉降,周边建筑物沉降,周边道路沉降,地下水位等计算数据与监测数据进行了对比分析,同时将PCMW工法与传统的钻孔灌注桩加止水帷幕的工艺进行对比.结果表明,PCMW工法的支护结构占地空间较小,对周边环境影响较小,有利于保护周边建（构）筑物;管桩的置换土仅为钻孔灌注桩的25%~35%,相对更为环保;水泥土搅拌桩内置预制高强预应力管桩,与水泥结合增加桩体强度.此外,PCMW工法具有较高的抗弯和抗剪强度,止水效果好,施工造价较低等优点.

Several parameters of the PCMW method were introduced in detail to check the embedded depth, bearing capacity, and stability. Taking a school underground garage excavation engineering of Nanjing as an example, this study compared and analyzed on the foundation pit supporting structure level, vertical displacement, lateral displacement of deep level land, support settlement, column axial force, settlement of surrounding buildings, the surrounding road subsidence, groundwater level data calculation and monitoring data. The technology of cast-in-place bored pile PCMW method and traditional and waterproof curtain was also compared. The results showed that the PCMW method of the supporting structure occupies less space, having less impact on the surrounding environment, and is conducive to the protection of the built around the building（structure）. Replacement pipe piles bored pile is only 25%-35%, which works relatively better in environmental protection;Cement soil mixing pile built in prefabricated prestressed high strength concrete pipe, coupled with cement improves pile strength and sealing effects, and it has higher flexural and shear strength with low construction cost, saving 20%.