素土挤密桩处理超高填方下深厚湿陷性黄土地基的试验研究  

On treating deep collapsible loess foundation by compiling earth to super high fills

作　　者：胡长明[1] 梅源[1] 王雪艳[1,2] 张文萃[1] 崔耀[1] 

机构地区：[1]西安建筑科技大学土木工程学院,西安710055 [2]西安建筑科技大学华清学院,西安710043

出　　处：《安全与环境学报》2012年第5期201-203,共3页Journal of Safety and Environment

基　　金：陕西省科技攻关计划项目(2011k10-20);包头市科技计划项目(2011x1006)

摘　　要：以某民用机场工程为背景,选取该机场拟建场区85 m黄土高填方所在位置作为试验区,开展素土挤密桩处理地基的试验研究。采用桩体动力触探试验、桩间土室内土工试验及现场载荷试验对处理后的地基进行检测,分析了各小区试验前后土体孔隙比、干密度、压缩模量、动力触探击数等物理力学参数的变化规律,得到了处理后的土体变形模量、地基承载力特征值及其对应沉降量。结果表明,采用素土挤密桩处理后湿陷性黄土地基桩体密实性较好,单桩承载力特征值较低,只有70～75 kPa,而单桩复合地基承载力特征值为240 kPa,与本区黄土承载力特征值相比有较大提高。处理后的地基土层干密度、孔隙比与处理前的平均参考值相比,基本没有变化,而压缩模量增幅较大,桩间土的湿陷性消除。桩间距越小,地基土的处理效果越佳,但处理效果受桩间距影响不显著。研究表明,采用冲击沉管或振动沉管工艺施工素土挤密桩,抱管及塌孔现象严重,工效不佳。施工工艺及参数应根据工程特点合理选择,才能同时满足地基承载力及施工工效的要求。The present paper is aimed at introducing our experimental research on building-up a thick highly collapsible loess foundation for a civil airport project by compiling soil as the background. This paper has selected the 85 m loess high fill location in the proposed zone for the airport as the experiment area, and carried out series of experimental studies for the given purpose. In achieving our goal, we have analyzed the changing regulaty of the physical and dynamical parameters of each area, including the void ratio, dry density, modulus of compressibility, dynamic penetration data, the deformation modulus of the soil to be treated, the characteristic features of the ground bearing capability and its corresponding settlements by means of pile dynamic strength, loess collapsibility test and the field loading test. The testing results we have gained indicate that the collapsible loess foundation piling-up and the singular piling load capability is comparatively low after the soil treatment, whose singular piling load bearing capability is just of 70-75 kPa, while the single pile composite foundation bearing capacity is equal to 240 kPa. Actually, what we have done can be thought of as a big progress in comparison with other foundations ever made in this area. However, the modulus of compression has greatly been increased after the treatment due to the removal of collapsible soil in the pile layers. The fact we can find is that the smaller the pile spacing is, the better the foundation treatment effect, though the influence of pile spacing on the treatment effect doesn＆rsquo;t seem to be obvious. Thus, our research results show that： use packed soil pile by impacting immersed tube or vibrating immersed, tube squibs and hole collapse were serious and the work effect was not good. Only choose advisable construction technology and indexes according to construction feature, it can satisfy need of foundation bearing capacity and work effect. The results of the tests can provide a reference to the same-kind of engine

关 键 词：土木建筑工程施工 素土挤密桩 湿陷性黄土地基 动力触探试验 载荷试验 

分 类 号：TU472[建筑科学—结构工程]