建筑垃圾再生材料灰土挤密桩成桩应用试验

为了掌握建筑垃圾再生材料在灰土挤密桩处理湿陷性黄土地基中的应用性能,首先通过材料力学性能试验确定了粒径为0～30 mm、建筑垃圾与灰土比例为72:28的建筑垃圾灰土挤密桩填料。然后完成了4组不同距径比的试桩应用试验,得到了不同距径比下的桩间土湿陷系数、桩间土挤密系数、桩间土静力触探曲线、复合地基荷载-沉降曲线等应用性能参数及特点。结果表明:桩间距越大,桩间土湿陷性系数越小; 距径比越小,桩间土挤密系数越大,桩间土的比贯入阻力越大; 在试验路段采用距径比2.25的建筑垃圾灰土挤密桩方案时,桩身容许承载力为175 kPa,复合地基承载力特征值为260 kPa,挤密效果良好; 成桩7 d浸水试验后复合地基承载力和桩身承载力平均下降14.3%,但仍满足桩设计要求; 研究结果验证了建筑垃圾再生材料灰土挤密桩处理湿陷性黄土地基的可行性,为工程应用提供性能参数参考,可进一步扩大建筑垃圾的使用范围。

Application Experiment of Construction Waste Recycled Lime Soil Compaction Pile

In order to master the application performance of construction waste recycled materials in the treatment of collapsible loess foundation with lime soil compaction piles, through the material mechanical performance test, the filling material of the lime soil compaction pile with the particle size of 0-30 mm and the ratio of construction waste to lime soil of 72:28 was determined firstly. Then, four groups of application tests of test piles with different distance to diameter ratios were completed, and the application performance parameters and characteristics such as the collapsibility coefficient of soil between piles, the compaction coefficient of soil between piles, the static penetration test curve of soil between piles, and the load-settlement curve of composite foundation under different distance to diameter ratios were obtained. The results show that the larger the pile spacing, the smaller the soil collapsibility coefficient between the piles. The smaller the distance to diameter ratio, the larger the soil compaction coefficient between the piles, and the greater the specific penetration resistance of the soil between the piles. When the construction waste lime soil compaction pile scheme with a distance to diameter ratio of 2.25 is adopted in the test section, the allowable bearing capacity of the pile body is 175 kpa, and the characteristic value of the bearing capacity of composite foundation is 260 kpa, and the compaction effect is good. After the 7 d immersion test of the pile, the bearing capacity of the composite foundation and the bearing capacity of the pile body decreased by 14.3% on average, which still met the design requirements of the pile. The research results verify the feasibility of treating collapsible loess foundation with lime soil compaction pile, which can provide performance parameter reference for engineering application and further expand the use scope of construction waste.