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云南地区普遍存在的泥炭质土对普通深搅桩和长螺旋钻孔桩成桩质量有非常大的影响。以官渡区文化生态新城-回迁安置房一期工程A地块基坑支护为依托,对水泥搅拌桩及长螺旋钻孔桩进行成桩试验,探讨了泥炭土中:有机质含量高这一特点对水泥搅拌桩成桩质量差、强度低的作用机理;高压缩性、孔隙比大、极松散等特点对长螺旋钻孔桩串浆及实际充盈系数过大的影响。针对上述作用机理对:搅拌桩的水泥掺量、等级、施工工艺及外加剂四个方面同时改进;长螺旋钻孔桩在泥炭土层厚度>3 m段采用桩周设置封闭帷幕的方式防止其水泥浆的流失等措施。结果显示对水泥搅拌桩及长螺旋钻孔桩的成桩质量有较大改善。希望能给相关工程提供借鉴意义。
The common peat soil in Yunnan area has a very big impact on the pile quality of ordinary deep-pile and long-auger bored pile. Taking Guandu District Cultural and Ecological New Town - Relocation and Resettlement House Phase I project as foundation pit support, cement mixing piles and long auger bored piles were put into pile test to study the peat soil: the characteristics of high organic matter content The effect mechanism of poor quality and low strength of cement mixing pile into piles; the effect of high compressibility, large void ratio, very loose and other characteristics on the stringing of long spiral bored piles and the actual filling coefficient. Aiming at the above mechanism, the four aspects of cement content, grade, construction technology and admixture of mixing pile are improved at the same time. The long auger bored pile adopts the method of setting the closed curtain at pile circumference to prevent it Loss of cement and other measures. The results show that the quality of cement mixing pile and long spiral bored piles have greatly improved. Hope to provide reference for the relevant projects.