深层水泥土双向搅拌桩强度试验研究

Experimental Study on Strength of Bidirectional Deep Cement Mixing Piles

为了研究广州南沙地区深厚软土条件下水泥土双向搅拌桩桩身水泥土强度与土质类型的关系,对现场桩体抽芯试样进行了单轴无侧限抗压强度实验,获得了3种不同土质拌合的桩身水泥土的应力-应变曲线和桩身强度-深度的变化曲线。通过分析这些数据曲线,得知不同土质类型拌合的桩身水泥土强度差异很大,其中粉质粘土质桩身水泥土强度最高,淤泥质桩身水泥土强度较低。由于这种拌合土质类型的差异性,使得搅拌桩桩体强度随着地层土质的变化产生明显的分段性。对水泥土双向搅拌桩桩身水泥土平均抗压值强度fcu的取值进行了探讨,为钉形水泥土双向搅拌桩在广州南沙地区的应用提供了依据。

In order to study the relationship between strength of soil cement of deep mixing column and soil types under deep soft soil conditions in Nansha area of Guangzhou, uniaxial unconfined compressive strength tests were performed for core sample of deep mixing piles, thus the stress-strain curves of soil cement with three different types of soil, as well as strength-depth curves of the column body were obtained. By analyzing these curves, it is concluded that the strength of soil cement with different soils of the deep mixing column varies widely, among which the soil cement mixed with silty clay has the highest strength and those mixed with mud has the lowest. Due to the differences in the properties of mixing soil, the strength of mixing piles obviously changed in phases. Average compressive strength values （f∞） of soil cement was discussed, and the result obtained can provide a basis for application of bidirectional deep cement mixing piles in Nansha area.