水泥土搅拌桩空搅工艺在斜坡软土地基处理中的应用

Application of No Cement Mixing Process for Cement-soil Mixing Pile Applied for Treatment of Sloping Soft Soil Foundation

针对高原斜坡软土地基处理施工中,单向水泥土搅拌桩成桩困难这一问题,结合镇雄车站地基处理施工,通过灰色软黏土原状样与重塑样的室内试验分析表明:斜坡软土成因复杂,软土成分、土层性质差别大,是导致单向水泥土搅拌桩难以成桩的主因;通过对灰色软黏土原状样与重塑样的室内试验数据分析表明,这种斜坡软土经过扰动后,无侧限抗压强度为原状土的30%左右,黏聚力为原状土的15%左右。以此为依据,提出了“增加空搅”的正反向旋转水泥土搅拌桩施工工艺,并通过工艺试验确定了工艺参数,大大提高了成桩质量。

For the construction of sloping soft soil foundation on plateau,unidirectional soil-cement mixing pile was subject to difficult pile-forming;thus combined with the foundation treatment of Zhenxiong Station,the indoor tests on the undisturbed and remoulded samples of grey soft clay were conducted.The analysis shows that,sloping soft soil has complex genesis with great difference on the soil composition and characteristics,which is the main factor leading to different pile-forming of unidirectional soil-cement mixing pile.The data from the indoor tests on the undisturbed and remoulded samples of grey soft clay indicates that,after disturbance,the unconfined compressive strength of the sloping soft soil is only about 30%of that of the undisturbed soil,and the cohesion about 15%.On this basis,the construction technology for forward and backward rotating cement-soil mixing pile with“increased part of no cement mixing”was put forward and,after the processing parameters determined by tests,the pile-forming quality had improved greatly.