Advanced geological prediction with a multifunctional drilling rig is a method that uses advanced drilling supplemented by MWD (measurement while drilling) and geological coring to obtain information about the rock and soil hardness, water flow and pressure, cavities, fissures, gas, and other conditions ahead of the tunnel face.

DGZ150 series multifunctional drilling rig

The CRCHI DGZ150 series multifunctional drilling rig is specialized equipment developed for advanced geological prediction in tunnels with complex geology. It achieves a maximum drilling depth of 150 meters and a borehole diameter of ∅65–∅245 mm. It adopts key technologies such as a top-hammer power head with eight rotary gears and three impact gears, automatic drilling, dual power, wireless remote control, and high-altitude adaptability. It offers advantages including high safety, high efficiency, and strong adaptability to working conditions, and meets the construction requirements of advanced drilling, geological coring, pipe-roof support, grouting reinforcement, slope anchoring, and tunnel emergency rescue. It can be used in tunnels, culverts, and roadways for railways, highways, water conservancy, municipal engineering, and mining.

As a key national strategic project, the high-altitude and severely cold railway faces construction challenges such as towering mountains and steep ridges, topographic elevation differences, complex geology, mountain hazards, and low pressure and severe cold. The harsh construction environment is a great test for both personnel and equipment. The CRCHI high-altitude multifunctional drilling rig leverages its functional advantages in advanced drilling, geological coring, and advanced pipe-roof support to support the safe, environmentally friendly, and stable construction of high-altitude railway tunnels.

Advanced exploration hole construction site

The Kangding No. 2 Tunnel is located at an altitude of more than 3,000 meters and has complex geological conditions, including special unfavorable geology such as high ground temperature, high ground stress, rockbursts, water and mud inrush, and gas. It is an extra-long tunnel with considerable construction difficulty. Facing harsh construction conditions, the DGZ150G high-altitude multifunctional drilling rig demonstrated stable and efficient operating performance:

(1) A ∅76 mm advanced exploration hole 30 meters deep took 1 hour. After construction was completed, the measurement-while-drilling data were exported via USB drive or network cable, and MWD analysis software was used to generate geological cloud maps and log parameter curves to predict the geological information ahead.

Geological cloud map

Partial log parameter curves

(2) Wireline coring with a ∅76 mm borehole diameter and a ∅50 mm core diameter to a depth of 30 meters took 10 hours, accurately analyzing the surrounding rock information ahead and providing a reference for subsequent tunnel excavation.

Core samples

(3) Construction of ∅90 mm advanced pipe-roof holes 9 meters deep took 5 hours in total for 25 holes per cycle, ensuring the smooth installation of the pipe roof and achieving a good support effect.

Pipe-roof hole construction site

In addition, the DGZ150 series multifunctional drilling rig has been successfully applied in multiple tunnel engineering projects, including the Lhasa–Nyingchi Railway, Chengdu–Kunming Railway, Fuyi Expressway, Pingwu Expressway, Yunfeng Expressway, and Lixiang Expressway. Its advanced exploration holes meet customers' required depths of 35–80 meters. Whether in soft rock formations such as mudstone, shale, and gneiss or in hard rock formations such as granite and basalt, the drilling speed remains stable at 15–50 meters per hour, meeting the construction requirements of tunnel advanced geological prediction and water and pressure release, and demonstrating the multifunctional drilling rig's adaptability and reliability under different working conditions.

With the large-scale construction of railway, highway, water conservancy, municipal, and other projects, the number of tunnels is increasing. To ensure tunnel construction safety and accelerate construction progress, advanced geological prediction will become a key process in tunnel construction. CRCHI will, as always, adhere to the design concepts of independent innovation, high cost-effectiveness, and intelligentization in the R&D and technical upgrading of multifunctional drilling rigs, contributing to safe and efficient tunnel construction.