Anchor System Supply for Guizhong Expressway Section No.6 (Guangxi)
Guangxi Guizhong Expressway – Section No.6 (contracted by Huabang Construction Group) runs 17.99 km through mountainous terrain in Pingle and Gongcheng counties. The section includes 15 bridges (4.05 km) and 4 tunnels (4.02 km), giving a bridge‑tunnel ratio of 44.85%. High cut‑slopes (up to 60 m), long‑span continuous rigid‑frame bridges (main span >100 m), and a 4‑month rainy season pose major construction challenges.
Advanced prestressing technologies were systematically applied to overcome these difficulties: precast prestressed girders, permanent ground anchors, self‑drilling hollow bolts, intelligent post‑tensioning systems, prestressed rock bolts, and precast prestressed elements. The results include 30% reduction in on‑site curing time, zero landslide incidents, and 25% increase in tunnel advance rate.
| Construction Challenge | Description | Prestressed Solution |
|---|---|---|
High bridge‑tunnel ratio Bridge‑tunnel density | Bridge‑tunnel ratio reaches 44.85%, frequent transitions, difficult equipment mobilization, long on‑site casting period. | Precast prestressed concrete girders – central yard prefabrication + on‑site erection, reduces field casting and accelerates schedule. |
Deep cut slopes Up to 60 m high | Weathered rock slopes, high landslide risk during rainy season. | Permanent prestressed ground anchors (double corrosion protection, 1000‑2000 kN) – active slope stabilization, preventing collapse. |
Narrow tunnel portal Limited working space | Tunnel portals in narrow valleys, conventional rock bolt installation is slow. | Self‑drilling hollow grouting bolts – drilling, grouting and anchoring in one step; 50% faster installation. |
Long‑span rigid frame Main span >100 m | Cantilever casting requires strict stress and alignment control. | Intelligent post‑tensioning system (1860 MPa strands + digital jacks) – synchronous tensioning, real‑time monitoring, accurate closure. |
Tunnel fault zone Weak rock & water inflow | Fractured rock mass with groundwater, conventional support leads to large deformation. | Prestressed expansion rock bolts (500 kN) + steel‑fiber shotcrete – actively restraining rock deformation. |
Tight schedule 4‑month rainy season | Long rainy season shortens effective working window for concrete works. | Precast prestressed elements (retaining walls, culverts, etc.) – off‑site production + on‑site assembly, works even during rain. |
