振杆密实法处理湿陷性黄土地基试验研究

Field tests on improvement of collapsible loess by vibratory probe compaction method

湿陷性黄土地基加固处理是中国西部开发建设工程中面临的问题之一,且面广量大。振杆密实法技术处理湿陷性黄土地基,采用自主研发的振杆密实设备,以甘肃中兰铁路客专项目工程场地为依托,提出了气动振杆密实法处理湿陷性黄土地基的施工工艺,并对处理效果进行了测试评价。原位测试和室内试验结果表明:处理后黄土为非湿陷性,平均湿陷系数为0.003;处理范围内土层锥尖阻力、侧壁阻力和标贯击数较处理前显著提高,面波波速提高15%左右,且土层各项物理力学性能指标均有明显改善。结果表明振杆密实法是湿陷性黄土地基处理的一项全新技术,具有节能环保、经济高效等优点,在黄土地区有推广应用前景。

The improvement of collapsible loess is one of the technical problems in the development and construction of western China.The collapsible loess covers a large area,and there are many ground treatment projects under construction.The vibratory probe compaction method is first proposed to treat collapsible loess.During the project of Zhongwei-Lanzhou high speed railway,the technology of pneumatic vibratory probe compaction method to treat collapsible loess is proposed by using the self-developed vibratory probe compaction equipment,and the treatment effect is evaluated.The results of the in-situ and laboratory tests show that the collapsibility of subsoil is eliminated after treatment,with an average collapsibility coefficient of 0.003.The cone resistance,sleeve friction and SPT blow counts in the treated soil are significantly higher than those before treatment.Moreover,the surface wave velocity of subsoil increases by 15%and its physical and mechanical properties are also significantly improved.The vibratory probe compaction method is effective for the treatment of collapsible loess.The new construction technique is energy-efficient,environment-friendly,fast in construction and low-cost,and it can be applied in loess areas.