基于时空四维点云的采动巷道变形精细解析与应用研究

Fine-grained analysis and application study of mining-induced roadway deformation based on spatiotemporal 4D point clouds

  • 摘要: 针对传统矿山巷道围岩变形监测布线安装复杂、单点监测空间覆盖度低以及在非均匀变形环境下精度受限等问题,构建采动巷道全断面、全过程高精度量化解析与差异化协同控制的技术体系。提出一种基于时空四维点云的巷道变形精细解析方法,集成同时定位与地图构建(Simultaneous Localization and Mapping,SLAM)技术和惯性测量单元(Inertial Measurement Unit,IMU)的便携式移动三维激光扫描系统,获取巷道多时相高保真三维点云,在此基础上设计Two_Stage变形分级优化算法,第一阶段利用法向量和圆柱投影进行变形粗计算,以快速定位关键变形区域,第二阶段基于严格几何约束和位移向量对超限核心点进行精细计算,以减弱几何平均弱化效应并提高非均匀变形表面的解析精度,最后结合分布式锚杆(索)应力监测数据,构建支护体—围岩协同承载效率指数(Support-Rock Synergistic Bearing Efficiency Index),实现支护效能的量化评价。不同变形梯度试验中,Two_Stage算法的平均绝对误差为0.048 3 m,相比多尺度模型到模型点云对比(Multiscale Model-to-Model Cloud Comparison,M3C2)和点到点云对比(Cloud-to-Cloud,C2C)方法,测量精度分别提高68.7%和82.6%。结果表明:小煤柱回采巷道变形具有时空异性特征,空间上表现为以底鼓为主导且小煤柱帮变形更剧烈的非对称形态;时间上呈现工作面前方约150 m范围内超前剧烈影响与采后滞后变形2个阶段。定量分析结果显示,小煤柱帮SEI值约0.25 MPa/mm,仅为实体煤帮的1/3,反映出该侧存在高变形、低应力的力学解耦现象。小煤柱帮非对称大变形主要源于围岩破碎导致的锚固系统承载效率降低。基于变形—应力协同监测结果,构建切顶卸压优化应力环境+底板注浆抑制隆起+长锚索深部补强的非对称协同控制技术,现场监测表明该方案能够抑制侧向应力向巷道集中并重塑深浅部岩体协同承载关系,形成从全断面变形监测与失稳诊断到靶向智能控制的闭环技术路径。

     

    Abstract: To address the problems of complex wiring and installation, low spatial coverage of single-point monitoring, and limited accuracy under non-uniform deformation in conventional roadway surrounding rock deformation monitoring, a technical framework is established for high-precision quantitative analysis and differentiated synergistic control of mining-induced roadway deformation over the full cross-section and entire lifecycle. A fine-grained roadway deformation analysis method based on spatiotemporal 4D point clouds is proposed. A portable mobile 3D laser scanning system integrating simultaneous localization and mapping (SLAM) and an inertial measurement unit (IMU) is developed to acquire multi-temporal high-fidelity 3D point clouds of the roadway. Based on this, a Two_Stage hierarchical deformation optimization algorithm is designed. In the first stage, normal vectors and cylindrical projection are used for coarse deformation computation to rapidly locate key deformation regions. In the second stage, strict geometric constraints and displacement vectors are employed to perform refined computation for core points exceeding deformation thresholds, thereby mitigating the geometric-mean weakening effect and improving the analysis accuracy for non-uniformly deformed surfaces. Finally, by incorporating distributed anchor bolt (cable) stress monitoring data, a support-rock synergistic bearing efficiency index is constructed to enable quantitative evaluation of support effectiveness. Under different deformation gradient experient, an average absolute error of 0.0483 m is achieved by the Two_Stage algorithm. Compared with the multiscale model-to-model cloud comparison (M3C2) and cloud-to-cloud (C2C) methods, the measurement accuracy is improved by 68.7% and 82.6%, respectively. It is shown by field applications that the deformation of small coal pillar roadways exhibits pronounced spatiotemporal anisotropy: spatially, an asymmetric pattern dominated by floor heave is presented, with more severe deformation on the small coal pillar side; temporally, two stages are characterized by intense advance influence within about 150 m ahead of the working face and post-mining lagging deformation. It is indicated by quantitative analysis that the SEI value on the small coal pillar side is about 0.25 MPa/mm, only one-third of that on the solid coal side, and a mechanical decoupling phenomenon of “high deformation and low stress” on the small coal pillar side is revealed. The large asymmetric deformation on the small coal pillar side is mainly attributed to reduced anchorage system bearing efficiency caused by surrounding rock fragmentation. Based on the coupled deformation-stress monitoring results, an asymmetric synergistic control technology is developed, combining roof cutting for pressure relief to optimize the stress environment, floor grouting to suppress heave, and deep reinforcement with long anchor cables. It is demonstrated by field monitoring that lateral stress concentration toward the roadway is suppressed and the synergistic bearing relationship between shallow and deep rock masses is reshaped by this scheme, thereby forming a closed-loop technical route from full-section deformation monitoring and instability diagnosis to targeted intelligent control.

     

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