深层水泥搅拌桩内插钢筋混凝土预制桩

【摘要】在软土地质、地下水位较高的地区，目前应用于4.5～6.5m以内浅基坑的支护方法较多，如重力坝式挡土墙支护结构、钢板桩、拉森桩支护等形式。

其中，重力坝式挡土墙支护结构的挡土、止水效果最好，应用最广泛。该支护结构又细分为，桩顶不去土放坡的多排水泥搅拌桩支护结构、桩顶去土放坡的多排水泥搅拌桩支护结构、桩顶去土放坡的多排连拱型式水泥搅拌桩支护结构。

在实际应用中，以上的各种支护形式仍然存在一些需要进一步克服的问题，如需要较大的施工场地，或费用相对较高，或需要敞开降水，或稳定性不好、或支护结构变形较大且易脆性破坏等弊端。为了更好的解决上述问题，方便现场施工，在保证支护结构安全性能的前提下，我们提出了“劲性搅拌桩浅基坑支挡工艺”，其主要支护结构采用“深层水泥搅拌桩内插钢筋混凝土预制桩——劲性搅拌桩”，并编制“劲性搅拌桩施工工法”。

【关键词】水泥搅拌桩;基坑变形;劲性搅拌桩;复合围护结构

Precast reinforced concrete piles inserted within the deep cement mixing pile

——Jin mixing pile construction method

Sun Yao

（Tianjin Vocational College of Land Resources and HousingTianjin300270）

【Abstract】In soft soil quality， high water table areas， currently used within 4.5 ～ 6.5m support methods are more shallow pit， such as Gravity retaining wall supporting structure， steel sheet piles， piles retaining Larsen et form.

Among them， retaining Gravity retaining wall supporting structure， sealing the best， the most widely used. The supporting structure is subdivided into， do not pile soil grading of multiple rows of cement mixing pile retaining structures， pile to soil grading of multiple rows of cement mixing pile retaining structures， pile to soil grading more Pai even arch-style cement mixing pile retaining structure.

In practice， the above various forms of support there are still some issues require further overcome， such as the need for a large construction site， or a relatively high cost， or need open precipitation， or poor stability， or supporting structure large deformation and easy to brittle fracture and other defects. In order to better solve the problems， to facilitate the construction site， to ensure the safety performance of the supporting structure of the premise， we propose a "mixing pile shallow pit retaining process"， whose main support structure using "deep cement mixing pile interpolation reinforced precast concrete piles - mixing pile， "and the preparation of" mixing pile construction method. "

【Key words】Cement mixing pile;Pit deformation;Mixing pile;Composite Retaining Structure

1. 工法特点

1.1结构稳定。

竖向支护结构采用“深层水泥搅拌桩内插钢筋混凝土预制桩——劲性搅拌桩”，在水泥搅拌桩施工完毕后的4～6小时内，用静压桩机插入预制钢筋混凝土方桩。提高了水泥搅拌桩的抗弯、抗剪能力，避免水泥搅拌桩脆性破坏、能有效控制基坑变形。

1.2无需设置内支撑体系，土方开挖机械效率高。

该支护工艺，无需设置内支撑体系，桩顶只做压顶冠梁;可以将双排水泥搅拌桩连成整体，有效控制基坑上口变形，土方开挖可最大限度的采用机械施工。……