振杆密实法处理湿陷性黄土施工参数确定现场试验
Experimental study on construction parameters of collapsible loess foundation treated by vibrating rod compaction method
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摘要: 为了确定振杆密实法处理湿陷性黄土地基的施工参数,利用自主研发的振杆密实法设备在湿陷性黄土地基场地开展现场试验研究,分析振动频率、钻头形式、喷气压力、振点间距对施工效率和处理效果的影响。试验结果表明:在该场地条件下,当振动频率为16 Hz,采用A型组合钻头能减少翼片土体黏结,施工速率和密实效果最优;0.8 MPa的高压喷气可辅助振杆下沉,该气压下地基土的承载力提升明显。采用上述参数,控制不同振点间距处理后的湿陷性黄土地基锥尖阻力和侧壁阻力提升约200%~300%,振点间距越小,加固效果越显著,但振点间距过小容易造成串孔现象,以1.2~1.4 m为宜。研究成果可为振杆密实法在湿陷性黄土地基中的进一步应用提供技术参考。Abstract: In order to determine the construction parameters of the vibrating rod compaction method to treat the collapsible loess foundation, the self-developed vibrating rod compaction method equipment is used to carry out field tests on the collapsible loess foundation site to analyze the vibration frequency, drill bit form, jet pressure and influences of vibration point spacing on construction efficiency and treatment effect. The test results indicate that under the conditions of the site, when the vibration frequency is 16 Hz, the use of A-type combined drill bits can reduce the adhesion of the fin soil, and the construction rate and compaction effect are the best. The high-pressure jet of 0.8 MPa can assist the sinking of the vibrating rod. Under this pressure, the bearing capacity of the foundation soil increases significantly. Using the above parameters, the cone tip resistance and sidewall resistance of the collapsible loess foundation after treatment with different vibration point spacings are controlled to increase by about 200%~300%. The smaller the vibration point spacing, the more significant the reinforcement effect, but the smaller the vibration point spacing is easy cause bonding, 1.2~1.4 m is appropriate. The research results can provide technical reference for the further application of the vibrating rod compaction method in collapsible loess foundation.