扩孔器在深层静力触探中的应用研究

Application Research on the Reamer to Deep Cone Penetration Test

研究目的:为解决常规静力触探不易穿透硬层、测试深度较浅、不能满足勘察设计要求的难题,提出了深层静力触探的方法,并通过多年深入研究得以实现。在深层静力触探中,采用加设扩孔器的方法,即在特定位置加设特殊结构的扩孔器,是实现深层静力触探的关键技术之一。本文从扩孔器的设计思路提出、研发分析、试验检验等方面进行分析研究。研究结论:(1)结合静力触探影响测试深度问题分析和相关行业应用扩孔器的相关设计思路,提出在深层静力触探中应用扩孔器的方法;(2)综合理论分析、模型试验和数值模拟的研究成果,确定在探头后部30 cm处加设纺锤形扩孔器方案;(3)试验检验表明,应用扩孔器能起到增大孔径,减小探杆摩阻力,增加有效贯入力的作用;(4)通过对比试验,应用扩孔器后测试数据显示与常规静力触探数据基本一致,验证扩孔器研发方案对测试数据影响较小;(5)本文提出的在深层静力触探中应用扩孔器的方法,对拓展静力触探技术和研发相关设备具有一定的参考意义。

Research purposes： To solve the limitation of depth of traditional CPT which could not meet the requirements of the survey and design in hard soil layers, the deep cone penetration test that has been proposed, has been accomplished several years ago. In Deep -CPT, the method installing the reamer at specific position with special structure is one of the key technologies of deep cone penetration test. The method design, mechanism analysis and field test of the reamer are introduced in this paper. Research conclusions： From the research on the application of reamer to Deep - CPT, the method installing the reamer in Deep - CPT has been proposed from references to the factor analysis of CPT and the reamer design ideas in exploration drilling and trenchless drilling. Through theoretical analysis, model tests and numerical analysis, the design of installing the reamer at 30cm position above the probe with fusiform structure has been accepted. The project examples prove that the reamer could expand hole to reduce side friction of cone rod and efficiently increase the depth of penetration test and have almost no effect on the results. Through contrast test, the test data after application of reamer matches up with the data of traditional CPT, the influence on test data of verifying the reamer development scheme is very small. In this paper, the application of reamer could give reference and guidance for the expansion of CPT and related equipment development.