2024

Slope Protection at LNG Terminal & CCPP

In addition to the rockfall barrier system, artificial ground support measures such as dry shotcrete application and rock bolting have been implemented to enhance slope stability by mitigating the risk of wedge failures and providing surface protection. The slope was reinforced using K250-grade dry shotcrete with a 10 cm thickness, combined with composite steel reinforcement comprising M5 black steel wire mesh rolls (2.1 m × 54 m) and 0.8-meter-long friction bolts with a 33 mm diameter. For deeper anchorage, fully grouted thread bars (25 mm diameter, 4.0 m length, 3-inch hole diameter) were installed, with pull-out tests showing an acceptance load of 120 kN.

An in-situ destructive test using 32 mm diameter thread bars with a 1.0 m bond length and 3-inch hole diameter revealed bond stress values ranging from 661 to 945 kPa, with failure occurring at the grout-rock interface. These test results offer valuable insight and should be utilized to further optimize future slope protection designs.
 

2024

Slope Protection at UG Kopra

The slope protection system for the UG Portal Kopra is designed to ensure long-term stability and safety through a combination of advanced reinforcement techniques. It includes the installation of cable bolts using PC single strand (15.24 mm, 1,860 MPa), each providing 12 tons of capacity per hole, with a total length of 10 meters (7 meters bond length and 3 meters free length), spaced at 2-meter intervals with a 3-inch hole diameter. 

Additionally, fully grouted 25 mm diameter thread bars with a yield strength of 400 MPa are installed, offering 5 tons per hole at a length of 3 meters, also spaced 2 meters apart. Sikagrout 200 PT is used as the grouting material, offering high compressive strength, early pull-out capability (within 7 days), zero bleeding, and increased productivity with consistent performance. 

Dry shotcrete is applied using fiber-reinforced mixtures, manually or with a Carmix self-loading mixer (3.5 m³ capacity). Friction bolts combined with wire mesh serve as composite support with shotcrete. For additional rockfall isolation and corrosion resistance, a steel-plastic geogrid replaces traditional chainlink mesh, enhancing durability along the slope face.
 

2024

Rockfall Barrier

A rockfall barrier (RFB) system with an energy absorption capacity of 2000 kJ has been installed along a 350-meter stretch of slope benches, spaced every 10 meters, to safeguard the LNG tank from potential rock boulder impacts resulting from geological discontinuities. This barrier placement was based on comprehensive rockfall trajectory simulations. The installation scope included grouting of rock anchors, erection of 5.0-meter H-beam steel posts, and the placement of both cables and mesh, all of which were efficiently completed within a two-month period.

The RFB 2000 kJ system comprises a high-resistance, hot-dip galvanized barrier structure capable of absorbing up to 2000 kJ of energy, with a residual height of 71.1% of its nominal height and a maximum elongation of 6.42 meters. The lateral and upslope anchors utilize 20 mm diameter flexible high-strength cables with a tensile capacity of 302 kN, drilled to a depth of 4.0 meters with 3-inch diameter holes. Acceptance test loads were recorded at 251 kN for lateral anchors and 182 kN for upslope anchors. Foundation anchors consist of fully grouted 32 mm diameter thread bars, also embedded to 4.0 meters with 3-inch diameter holes, and demonstrated an acceptance load of 189 kN.

2024

Geocell Concrete Infill at Low Flow Diversion

Geocell concrete infill combined with friction bolting has been successfully implemented for low-flow river diversion, offering a more effective and cost-efficient alternative to conventional methods such as concrete pouring and concrete canvas. This innovative approach enhances structural integrity while optimizing material usage and installation time. The system utilizes 10 cm thick HDPE geocells filled with K300-grade wet shotcrete reinforced with synthetic fibers to improve durability and crack resistance. To further stabilize the structure, 33 mm diameter friction bolts with a length of 1.50 meters are applied, anchoring the geocell system securely to the ground.