1449 3.3 Key Technologies of Surface Integrated Drilling-Exploration-Grouting for Long, deeply buried water diversion Tunnels 3.3.1 Long-Distance Precision Guided Drilling Technology A high-precision gyro inclinometer while drilling and a screw directional drilling system are employed for trajectory control (Figure 3). Through the integration of algorithm optimization and dynamic prediction adjustment methods, hole placement accuracy is controlled within 2.5–5.0 m outside the tunnel contour, with a long-section deviation rate of ≤ 2‰.A composite drilling process combining a screw motor and a top-drive drilling rig is adopted to address borehole collapse and severe fluid loss in high-stress fractured strata. In parallel, a highly adaptable and performance-controllable drilling fluid system, along with efficient lost circulation control materials, is developed. These materials exhibit low initial viscosity ranging from 27 to 45 s, high stability with a water separation rate of ≤ 1%, and a controllable gelation time of 1.2– 3.5 h, enabling the rapid plugging of severe lost circulation zones. Figure 3 – Wireless inclinometer while drilling 3.3.2 While-Drilling Exploration and Geological Identification Technology This technology integrates multi-source information, including while-drilling parameter perception, multi-method engineering logging, directional coring, and downhole geophysical prospecting, to establish a refined geological exploration system based on surface directional drilling. A coupled model incorporating rock mechanical characteristics is constructed to achieve preliminary stratum identification and early abnormal warning by real-time analysis of while-drilling parameters such as drilling pressure, torque, rotational speed, and mud properties. Multi-method logging techniques, including acoustic wave, resistivity, and electromagnetic wave logging, are implemented through drilling channels to invert lithology, water richness, and fracture development characteristics within a 30 m radius around the borehole . Directional coring is conducted in key abnormal sections to obtain direct parameters for engineering design. Then, multiborehole detection data are fused to construct a three-dimensional geological model ahead of the working face through data inversion, enabling macroscopic identification of fractured zone distribution, graded prediction, and precise evaluation of water richness, fragmentation degree, and water inrush risk, providing a reliable basis for grouting treatment schemes. 3.3.3 While-Drilling Exploration and Geological Identification Technology Centered on the "two-step" precise grouting process, this technology integrates special equipment and adaptive materials to ensure grouting treatment effects.
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