As urban subways, large hydropower and water conservancy projects, and ultra-deep foundation pits continue to increase, underground space development has become a trend in urban growth. As a leader in diaphragm wall construction, the double-wheel trench cutter has already proven its capabilities in these super projects.

As the core component of the double-wheel cutter for rock breaking, the cutting pick's cutting resistance and rock-breaking capability play a key role in the construction efficiency, cutting energy consumption, and operational stability of the double-wheel cutter.

Double-wheel cutter construction is mainly based on impact cutting, and the main alloy of traditional cutting picks is prone to brittle fracturing. To make double-wheel cutter picks "cut faster, last longer, and cost less," SANY has redesigned its double-wheel cutter picks and launched two dedicated models.

Design Highlights

① Alloy Redesign

Coarser-grain WC is used, with particle size increased by more than 25%; a higher proportion of Co binder, increased by more than 15%; and trace rare earth elements are added to improve alloy performance, giving the main alloy better toughness and superior impact resistance, effectively reducing the fracturing rate of the main alloy;

② Tooth Shape Redesign

By simulating the cutting trajectory of the double-wheel cutter, the overall design adopts an inverted cone shape, so that the tooth tip forms effective contact with the rock arc surface during cutting. The middle of the body adopts a concave arc design for smoother slag discharge;

③ Body Process Upgrade

The body uses special structural steel as the base material and adopts a warm forging process. Through four stages of graded heat treatment, the body features high hardness at the head and good toughness at the shank;

④ New Protective Alloy Technology

For the first time, a protective alloy is set on the shoulder of the body. Through an automatic inlay welding process, it fits tightly with the body, enhancing the wear resistance of the body head and significantly extending the service life of the body.‍

Case Sharing

Project Name: Shenzhen-Huizhou Intercity Dapeng Branch Line Pingshan Metro Station Project

Engineering Geological Overview: 0–23 m is plain fill + completely weathered granite; 23–30.5 m is moderately to slightly weathered granite, with uniaxial compressive strength up to more than 80 MPa

Diaphragm Wall Parameters: trench width 1.0 m, trench depth 30.5 m

Construction Method: 0–23 m constructed with a grab; 23–30.5 m constructed with a double-wheel cutter

Construction Model: SANY SDC120‍

"SANY cutting picks have high construction efficiency, are wear-resistant, and have a low alloy head cracking rate. We are satisfied with their performance." — Operator Wang

It can be seen that in moderately weathered granite strata, the SYC6030-22SDC has more than 30% lower pick consumption than similar products; in slightly weathered granite strata, the SYC6030-20SDC-H has 25% higher cutting efficiency than similar products and 20% lower pick consumption; the cutting pick cost per trench panel can be saved by more than 20%.

Conclusion

At present, double-wheel cutter construction is developing toward ultra-deep and ultra-hard strata, and harsh construction conditions place more demands on double-wheel cutter picks. SANY double-wheel cutter picks will continue to innovate based on research results on cutter wheel pick arrangement, providing customers with higher-quality pick products and services and safeguarding urban underground space construction.‍