基于微损旋压钻进信息的地铁沿线病害土强度分析方法研究

The collapse along metro lines affects urban traffic safety seriously. Soil strength which can be reflected by micro drilling information is the main basis for evaluating risk of collapse. But, the analysis method of disease soil has not been solved thoroughly. Using the combination methods of statistics, theory, experiment, numerical calculation and in-situ test, collapse types based on main controlling index partition of mixed strata, the surrounding load and moisture content are divided. The influence law of propulsion, rotational speed of drilling speed and torque for four kinds of typical soils is studied by experiment. Considering confining pressure and moisture content, the relationship of soil strength theory is set up. Critical condition and influence factors of break bulk per unit time within the process of bit drilling are studied. Based on Mohr-Coulomb criterion, the mechanism of drill ground by alternative action of pressure and reverse is analyzed. And then, mechanical model and functional theory are established. The field test and numerical results carried out by drilling test in Radar suspected disease, compared with the survey results, are used for validation analysis method. The results provide new ideas and new ways for rapid diagnosis and treatment of collapse disaster along metro lines.

地铁沿线塌陷严重影响城市交通安全，土体强度是评价塌陷隐患的主要依据，而病害土强度分析方法一直未得到彻底解决。项目采用实例统计、理论、实验、计算和现场应用结合的研究方法，分析地铁沿线塌陷成因与特征，划分以混杂地层、周围载荷和含水率为主控指标的塌陷类型。根据地铁沿线土层，建立4类土物理模型，研究推进力、转速对钻进速度及扭矩影响规律，建立粘聚力、内摩擦角与钻进关键参数内在联系。研究围压、含水率对实验土钻测特征的影响，建立考虑围压和含水率的土体强度理论关系。研究40mm直径尖齿复合片钻头旋压钻进启动条件，建立压扭双重作用力学模型，明确破土体积重要影响因素。在雷达疑似病害区域开展连续-非连续数值分析和现场测试，利用强度理论计算并给出随钻深的粘聚力、内摩擦角数值，与数值模拟和勘查结果对比，修正和验证强度理论关系，形成基于微损旋压钻进信息的病害土强度分析方法。为地铁沿线塌陷灾害快速精细诊治提供新方法。

地铁沿线塌陷严重影响城市交通安全，土体强度是评价塌陷隐患的主要依据。研究了40mm直径尖齿复合片钻头旋压钻进启动条件，基于集中载荷作用下半无限空间的弹性力学解及Mohr-Coulomb准则，建立了压扭双重作用力学模型，研究钻头压入深度与钻杆推进力及土体粘聚力、内摩擦角的内在联系，明确了破土体积重要影响因素，数值计算证明了随钻强度测试的可行性；分析了钻头刀具切削破土（岩）过程，建立了尖齿复合片切削破碎模型，提出了以反映钻孔阻力的参数直接定量评估地层强度的方法，并得到了钻进过程扭矩与地层承载力呈线性关系；研发了三维柔性边界加载（可完成大试件实验尺寸：长×宽×深=2m×2m×2m，可实现围压200kPa-10000kPa）和随钻强度测试实验装置（随钻可同时测量4类力学响应量：扭矩、转速、推进力和进尺速率），开展了4类土体随钻强度测试研究，得到了岩土材料承载力与钻测扭矩的线性拟合表达式为：Q=-2.75+4.58N，建立了粘聚力、内摩擦角与钻进关键参数内在联系；利用自主研发的随钻强度探测装置对城市地下工程岩土体强度进行测试分析，验证了测试技术的可靠性和有效性，并通过大量工程应用验证，不断修正土体强度量化关系和优化测试技术装置及方案，形成了基于微损旋压钻进信息的病害土强度分析方法，为地铁沿线塌陷灾害快速精细诊治提供新方法。