Rock Support Design Research Articles

Scaling Laws for the Design of Rock Support

The dynamic loads imposed by rockbursts initiated by remote seismic events are directly related to the resultant ground motions. Consequently, the first step in the design of systems for the support of openings subject to such loading is to assess the ground motion characteristics; i.e., to evaluate the peak particle velocity ppv in the design region. Design scaling laws, relating seismic source intensity (event magnitude, radiated energy or a combination of seismic moment and stress drop at the source) to the peak ground motion characteristics at a target (e.g., a development drift or a stope) some distance from the source, are developed, based upon theoretical considerations and supported by a world-wide database. These scaling laws reflect the most relevant, critical conditions for engineering design.

Design and underground construction at the Xiaolangdi multipurpose dam site

The Xiaolangdi Multipurpose Dam Project on the Yellow River near Luoyang, Henan Province of the People's Republic of China, involves design and excavation of 19 water conveyance tunnels, several access tunnels, a large number ofgrouting and drainage adits, and an underground powerhouse complex. This paper describes some aspects relating to the design of excavation and rock support of the tunnels, varying in diameter from 8 to 18.5 m, and the powerhouse complex. The rock consists of interbedded sandstone, siltstone and claystone. Close to very widely spaced beddingplanes dip at an angle of 8° to 10°, towards east.

Comparison of predicted and measured performance of a large cavern in the Himalayas

Detailed investigative and performance monitoring studies have been carried out at the site of an underground powerhouse cavern in the Himalayan Region of India. The updated empirical (Q-system) and numerical (UDEC-BB) approaches, applied for predicting the behaviour of the rock mass prior to the construction of the underground cavern (20 × 49 × 216 m), have been compared with the instrumentation data from multi point borehole extensometers (MPBX). Upon completion of the first numerical excavation step (20 m span arch), a relatively high stress-strength ratio and a maximum deformation of approx. 18 mm was predicted in the roof of the cavern. MPBX readings in the arch have indicated maximum deformations in the range 19–24 mm with the 20m span fully excavated. The results of numerically excavating the cavern to its full height (49 m), have indicated maximum deformations in the range 43–45 mm in the walls of the cavern. Upon completion of the ongoing benching operations, the measured performance from the walls of the cavern will be available for comparison with the existing numerical results. Permanent rock support in the cavern consists of systematic bolting of alternating lenghts and mesh reinforced shotcrete S(mr). However, rock support design recommendations based on the Norwegian Method of Tunnelling (NMT), which employs wet process fibre reinforced shotcrete S(fr) instead of S(mr), have been numerically tested and verified.

Characterizing rock masses by the RMi for use in practical rock engineering: Part 1: The development of the Rock Mass index (RMi)

The Rock Mass index, RMi, has been developed to satisfy a need for a strength characterization of rock masses for use in rock engineering and design. The method gives a measure of the reduction of intact rock strength caused by discontinuities given by RMi = σ · JP. Here, σ is the uniaxial compressive strength of the intact rock measured on 50 mm diameter samples, and JP is the jointing parameter which is a combined measure of block size (or intensity of jointing) and joint characteristics as measured by joint roughness, alteration and size. This paper describes the method of determining the RMi for a rock mass using various common field observations. The determination of a meaningful equivalent block size is a key issue which is discussed in detail. Several areas of application of the RMi are presented, among others for design of rock support. Discussion of these applications will be developed in Part 2 of this paper.

Rock mechanics aspects of the ESF design : Mrugala, M; Bonabian, S Proc 1st Annual Topical Meeting on High Level Radioactive Waste Management, Las Vegas, 8–12 April 1990V1, P44–50 Publ ANS/ASCE: La Grange Park, 1990

Selected aspects of the ESF rock mechanics design are outlined with emphasis placed on specific requirements imposed on the design process conducted within quality assurance-controlled environment. Limited discussion is devoted to general approach used in rock support design.

Design of rock support for a major urban highway tunnel : Kitagawa, T; Rohde, J K G Proc International Symposium on Large Rock Caverns, Helsinki, 25–28 August, 1986V2, P1281–1292. Publ Oxford: Pergamon Press, 1986

Design of rock support for a major urban highway tunnel : Kitagawa, T; Rohde, J K G Proc International Symposium on Large Rock Caverns, Helsinki, 25–28 August, 1986V2, P1281–1292. Publ Oxford: Pergamon Press, 1986

Design of rock support for a major urban highway tunnel : Kitagawa, T; Rohde, J K G Proc International Symposium on Large Rock Caverns, Helsinki, 25–28 August, 1986V2, P1281–1292. Publ Oxford: Pergamon Press, 1986

Design of rock support for a major urban highway tunnel : Kitagawa, T; Rohde, J K G Proc International Symposium on Large Rock Caverns, Helsinki, 25–28 August, 1986V2, P1281–1292. Publ Oxford: Pergamon Press, 1986

Rock support design in good quality rock; three case histories : Humphries, R W; Lang, P A Proc International Symposium on Large Rock Caverns, Helsinki, 25–28 August 1986V1, P97–107. Publ Oxford: Pergamon Press, 1986

Rock support design in good quality rock; three case histories : Humphries, R W; Lang, P A Proc International Symposium on Large Rock Caverns, Helsinki, 25–28 August 1986V1, P97–107. Publ Oxford: Pergamon Press, 1986