Enhanced method for clamping rock bolt

Purpose and goal

The main objective of the project was to develop an expansive cementitious dry mortar filled in paper packets to install under the dome plates during installation of rock support systems in underground infrastructures. The final product was supposed to fill all the cavities and air voids under the dome plates to prevent the ingress of water and the associated corrosion.

Expected results and effects

The final solution is simple, cost-effective and easy to install and can facilitate quality control and documentation during installation. In addition, material waste will decrease and productivity will increase compared to current technology. In terms of working environment, the new technique will reduce the physical fatigue and risk of contamination as well as the mental stress of the workload as a result of the improved assembly process. Finally, the product can increase service life and reduce the need for inspection and maintenance during operation and thus the life cycle cost.

Planned approach and implementation

The project consisted of five WPs. In WP1, a dry mortar with the required expansion and strength properties and setting and hardening time was developed. In WP2, a paper with desired strength property in both dry and wet conditions, sufficient stretch ability and low permeability in lateral directions was selected. In WP3 and WP4, several prototypes were produced and tested in both the lab- and the field-conditions to evaluate the efficiency of the method. Finally, in WP5 the environmental impacts, cost analysis and comparison of the new method with the traditional ones were conducted.