平凉湿陷性黄土地区灰土挤密桩的应用效果评价

Evaluation the Compacted Soil-Lime Mixed Column Improving Collapsible Loess Soils in Pingliang Area

平凉-绵阳高速公路甘肃平天段庄浪县内广泛覆盖II^IV级湿陷性黄土,为有效消除黄土地基的湿陷性,提高复合地基的承载力及减小地基的不均匀沉降,选用了灰土挤密桩对湿陷性黄土地基进行处理,通过K112+262.0~292.0为首件工程的施工与检测,对平凉湿陷性黄土地区灰土挤密桩的应用效果进行了评价,发现灰土挤密桩可有效提高原有黄土的湿密度、降低初始含水率、提高原有地基的承载力,表明灰土挤密桩处理湿陷性黄土地基可行有效,最后总结了灰土挤密桩处理平凉湿陷性黄土地基的施工要点和相关经验,以供参考。

The Grades II^IV Collapsible loess soils are widely deposited in Zhuanglang County,Gansu Province,along the alignment of Construction segment of Pingtian of Pingliang-MianyangExpressway Project.The compacted soil-lime mixed column method was selected to effectively eliminate the collapse when wetted,to improve the bearing capacity of the improved soils and to minimize the potential differential settlement of foundations.The effect of the soil improvement method was first evaluated in stations between K112+262 and 292.The evaluation results indicate that,the compacted soil-lime mixed columns can effectively increase the natural unit weight of the collapsible soils,reduce the initial moisture content and improve the bearing capacity of native soils.The key points of the column installations and lessons learned during the construction are also summarized in the paper.