非开挖水平定向钻进导向孔的轨迹控制

在非开挖水平定向钻进(HDD)穿越施工过程中,为了避免钻具损坏地下管道,降低工程风险,需要控制穿越轨迹,其中导向孔的施工是最关键的工序之一。通过分析钻具性能参数及地层条件因素,建立了导向钻头在地层中造斜时的造斜强度和曲率半径计算模型。在施工的入土端,利用模型计算得到为钻进预定深度所需要的造斜起点及造斜距离;在施工的出土端,由已知的造斜起点计算造斜距离,确保最终按照设计要求平滑钻至出土点(坑)。使用该方法可以达到轨迹控制的要求,通过工程实践验证了其实用性。

Direction control technique of pilot-hole deflecting interval in horizontal directional drilling using trenchless way

In the process of the trenchless horizontal directional drilling(HDD) crossing installation,proper control on the undercrossing trajectory is needed for fear of drilling into the existed pipeline in order to reduce engineering risks.Among which,however,the construction of pilot hole is the first and foremost workstage of it.In this paper,the performance parameters of drilling tools together with stratum condition factors are analyzed to build a computation model of curvature radius and the inclination strength when pilot guide bit deflects into the stratum.The kick off point(KOP) and deflecting distance required to reach the preseted depth can be calculated by the computation model in the entrance;then in the exit,deflecting distance will be calculated by given KOP.This will ensure the bit drilling out of soil smoothly to the point and reach the goal of trajectory controlling.Finally,the practical applicability of this technique will be further proved in engineering practice.