Winning big! Winning big! The Jintai SX series dual-wheel milling machine has quietly accomplished another major feat in the Luotie Reservoir water conveyance tunnel. In response to widespread customer demand and to further comprehensively solve underground construction challenges, the Jintai "craftsmen's" painstaking masterpiece, the SX40H, has officially rolled off the production line, successfully taking on the Tiegang Reservoir tunnel project - Tiegang working shaft - with rock strength exceeding 100 MPa and a depth of 60.8 m. According to statistics, the Jintai SX series dual-wheel milling machines have participated in more than half of the mainstream diaphragm wall construction for the Pearl River water resources allocation project and its supporting works, making them a truly mainstream choice**!

Luotian Reservoir - Tiegang Working Shaft

The Luotian Reservoir - Tiegang Working Shaft is a supporting project of the Pearl River Delta water resources allocation project within Shenzhen. It is a key project for realizing the two-way allocation of water from the East and West Rivers in Shenzhen and a dual-water-source, dual-safety water supply layout. Its water supply coverage includes nearly 600 square kilometers of land in Bao'an District and Nanshan District, serving more than 6 million permanent residents and supporting a regional GDP of over one trillion yuan. The total investment of the project is 5.8023 billion yuan. The water conveyance main line is 21.68 km long, with a flow cross-section diameter of 5.2 m.

Tiegang Working Shaft - Project Plaque

Geological conditions: The upper part consists of artificial plain fill and Quaternary residual slope deposits. The lower part consists of monzogranite, which can be divided by depth into completely weathered, strongly weathered, and weakly weathered zones. The upper stratum is 34-48 m deep, and the lowest 3 m of the lower part is weakly weathered granite with hardness above 100 MPa.

Tiegang Working Shaft - Rock Sample

Construction difficulties: The project's stratum has high rock density and hardness (local hard strata reach strengths above 150 MPa) and great depth. Maintaining verticality during rotary drilling for guide holes is highly difficult, which in turn affects the verticality during dual-wheel milling construction and greatly increases the construction difficulty of the secondary-phase trench sections.

Construction process: The project adopts a composite process of "drilling," "grabbing," and "milling." A Jintai SH38 rotary drilling rig drills the guide holes, an SG50 grab completes trenching, and the SX40H completes the final trench milling process. The diaphragm wall of the Tiegang working shaft is divided into 20 trench sections in total, with 10 primary-phase trench sections and 10 secondary-phase (Phase II) trench sections. The primary-phase trench sections are formed by three milling passes, and the Phase II trench sections are formed by one milling pass. For the primary-phase trench, the side trench along the centerline of the trench section is 2.21 m long, the middle trench is 1.97 m long, and the trench section is 6.39 m long in total; the Phase II trench is 2.80 m long. The overlap length between the primary-phase and Phase II trench sections on the diaphragm wall axis is 35 cm.

Construction progress: The Jintai SX40H has now completed 3 trench sections, with depths of 60.8 m, 56.9 m, and 53.4 m respectively. The time taken was 60 hours, 40 hours, and 60 hours respectively.

The SX40H is a new air-lift reverse circulation dual-wheel milling machine from Jintai, newly equipped with a hose slag discharge system. This dual-wheel milling machine completely solves the pain points of manual disassembly and connection of slag pipes and elbows, featuring efficient and thorough slag discharge, convenient assembly and disassembly, and economical maintenance. Its core components still adopt internationally renowned brands, ensuring efficient, stable, economical, and environmentally friendly construction while also making the whole machine highly cost-effective.