利用旋挖机实时钻进参数判定持力层的方法

旋挖钻机作为当前嵌岩桩成孔的一种重要的快捷施工方式,优势显著。其钻进过程中在线监控系统实时监测的随钻参数不仅仅可作为施工操作的主要依据,还可为嵌岩桩持力层的判定提供基础性数据。鉴于施工场地赋存环境的复杂性,钻进中必然导致钻进率、钻杆钻速、给进力、动力头扭矩等随钻参数的时空演化。根据采集的随钻参数数据库及理论分析,建立随钻参数随钻进深度的变化曲线,结果表明单因素变化曲线不能准确识别持力层。在此基础上,进一步提出基于多因素协同控制的持力层判定方法,建立岩体荷载强度模型进行基于随钻参数综合指标的持力层判定。采用该模型分析旋挖钻进过程中持力层岩体的强度和承载力,与地质勘测中的岩体强度测试结果对比,所判定的持力层特征符合实际。由此可见,基于随钻参数的持力层判定方法进行钻进过程中的岩层特性确定及持力层判定是可行的,可用于不同赋存环境下钻进过程中的持力层辨识。

An identification method of the bearing strata based on real-time drilling parameters of rotary drilling rigs

As an important and fast construction method for drilling holes, rotary drilling rig is superior to other drilling machines. The drilling parameters based on the online monitoring system which we can get from the drilling process provide not only significant information for construction operation, but also original data for identification of the bearing strata. Due to the complex original site environment, the drilling parameters such as drilling rate, rotation rate, rotary force and torque of the power head would be changed with time and space during the drilling process. According to the parameters database and theoretical analysis, the curves of drilling parameters varying with drilling depth are establishecl, from which we can find that the single-factor curves cannot identity the bearing strata accurately. In addition, a multi-factor collaborative control method for identification is proposed, and a load-strength model of the rock masses is built to determine the bearing strata, which is based on comprehensive index and all the drilling parameters are included. And then the model is applied to analyze the strength and bearing capacity of the formation considering the rotary drilling. By comparing the analysis results with the results from strength testing values in the geological survey, we can find that the strata property identified by the proposed method is in accordance with the real characteristics. Therefore, the above identification method based on drilling parameters is rational and reliable to determine the strata properties and identify the bearing strata, and it could be used for formation identification considering drilling process under different geological environment.