Selecting the suitable rock excavation method of hard rock removal for constructing a ground level service reservoir at hill top in urban population

Stability analysis of vertical excavations in hard rock by integrating a fracture system into a PFC model

EPB tunnelling in highly variable ground – the experience of Oporto Light Metro

Chapter-20 - Method of excavation

Chapter 21 - Method of Excavation

Introduction. Single-bucket excavators with both flexible and rigid suspension of work equipment are actively engaged in construction, stripping work and production mining. Excavators with rigid suspension are commonly used in construction, while excavators with flexible suspension are used in mining practice. This work considers the process of excavating rock with a single-bucket hydraulic backhoe excavator. The reliability and durability of excavators depend on the correct choice of the parameters of work equipment elements. Research objective is to determine the maximum turning force of the bucket of a hydraulic backhoe excavator, taking into account soil friction against the bucket bottom and side plates during rock excavation. Methods of research. When the maximum force on the bucket turning hydraulic-cylinder rods in the course of rock excavation is analytically defined, it is advisable to consider digging a trench in plain surface or in the open-pit in plain surface of a stope face provided that per one turn the bucket is filled to capacity. In this case, a segment of soil cut from the rock mass has maximum depth of cut as compared to other excavation methods. Total excavation resistance includes: resistance arising from cutting rock with a bucket with maximum depth of cut; resistance associated with the impact of gravity of the rock mass on the bucket; resistance associated with rock mass friction against the bucket bottom; resistance associated with rock mass friction against the inner surfaces of the bucket side plates. Results. The dependence has been determined between the maximum force on the bucket turning hydraulic-cylinder rods and bucket design parameters as well as the physical and mechanical characteristics of the face rock. The results analysis showed that both excavation process flow scheme and rock characteristics have a significant influence on the total bucket excavation resistance. Conclusions. The developed method of calculating the excavation resistance takes into account the internal forces of bucket interaction with rock and makes it possible to increase the accuracy of maximum digging force calculation. It therefore becomes possible to more reasonably approach the choice of the excavator bucket turning hydraulic cylinder parameters and thereby increase the reliability and durability of the machine as a whole.

There are cases where excavations in hard rock must occur very close to existing pipes that must remain in operation. These cases include new gas or water pipes in existing Rights-of-way (ROW) where separation between new excavation trenches and existing pipes is very limited. In other instances, hard rock or mass concrete must be excavated to install new pipes or other facility upgrades near critical utility pipes or operating penstocks at hydroelectric plants. In these cases where excavations in hard rock must occur very close to existing pipes, the use of blasting methods is not possible when standard vibration criteria or restrictions based on pseudo-theoretical calculations are applied to the work. However, mechanical methods are often impractical when the rock is too hard, volume of rock is too large, or excavation geometries prevent their use. This paper focuses on systematic methods that can be used to develop customized blasting programs based on existing pipe(s) condition, strain failure modes, ground characteristics, and close-in blasting experience. The application of these methods is demonstrated in two case-history summaries including blasted rock excavations located within 1 m of steel penstock pipes and 2.4 m from steel water mains.

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the 43rd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Sept. 29-Oct. 2, 1968. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract The surface active agents and continuous gas lasers are found to be effective in reducing the strength of hard rocks when tested in bending. The observed reduction in strength, when the rock specimens are subjected to laser irradiation is due to thermal stresses developed within the specimens. Stress activated corrosion is considered to be the main cause of loss of strength when surfactants are used. Introduction Deep tunnels are suggested as a possible guideway for high speed ground possible guideway for high speed ground transport systems in the Northeast corridor to relieve the frequent air and land transportation congestion. The great flexibility in route location, lack of any significant interference with existing activities, excellent isolation and safety to public, and negligible cost of right of way have made the tunnelling an attractive possibility for such a guideway. One of the major problems associates with the construction of a deep tunnel is the tunnel driving technique and the slow rate of advance of the heading associated with such an operation, especially in hard rocks. The tunnelling operation in hard rocks basically involves fracturing and disintegration of rock masses and the removal of debris. Slowness of the conventional method of tunnelling is primarily due to the discontinuous nature primarily due to the discontinuous nature of the operation, whereby different steps of drilling, charging, blasting, ventilating and removal of debris have to be performed in a repetitive manner. A performed in a repetitive manner. A variety of techniques of breaking rock masses is suggested in the literature which attempt to provide a continuous tunnelling operation or to reduce the number of steps in conventional tunnel driving. It is apparent from a review of these methods, however, that a fundamental understanding of the failure of rocks and the factors controlling it is important for the development of a rapid method of excavation in hard rocks.

Planning, investigation and preliminary design for the Eastern distributor tunnels — Sydney : Baxter, D A; Chappel, R A; Fishburn, B R Proc 6th Australian Tunnelling Conference, Melbourne, March 1987V1, P55–65. Publ Parkville: AusIMM, 1987

Research Article| January 01, 1996 Support of Underground Excavations in Hard Rock JOHN COGAN JOHN COGAN Morrison Knudsen Corporation, One Market Plaza, Stewart Tower, Suite 400, San Francisco, CA 94105 Search for other works by this author on: GSW Google Scholar Environmental & Engineering Geoscience (1996) II (4): 610–611. https://doi.org/10.2113/gseegeosci.II.4.610 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation JOHN COGAN; Support of Underground Excavations in Hard Rock. Environmental & Engineering Geoscience 1996;; II (4): 610–611. doi: https://doi.org/10.2113/gseegeosci.II.4.610 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Rock mechanics considerations for drilled or bored excavations in hard rock

Analysis of factors influencing vibration reduction and design optimization of damping holes in adjacent tunnel blasting

Interest in compressed air storage has been developing in Sweden, Finland, Denmark, England, and France, as well as the United States. One commercial unit is under construction in Huntorf, West Germany. Compressed air for peak power can be stored either in natural or man-made caverns. Only new excavations in hard rock down to depths of about 2500 feet are considered in this report. In 1974, conditions for underground storage were discussed in a Geological Survey of Potential Cavern Areas in New England, referred to as the CAINE report. In this survey of the northeast region, the rest of the corridor between Washington and Boston has been added. The rock formations in the entire area of about 45,000 square miles are evaluated. The physical properties of rocks and criteria for their evaluation in underground openings are discussed. Methods of rock excavation and the basis for selecting areas are considered. Information on bedrock units along the corridor is reviewed. A list of favorable rock formations is included.

The first step in mining activities is rock excavation in both mine development and production. Constant pressure for cost reduction and creating an improved/safe work environment for personnel has naturally resulted in increased use of mechanical excavation systems in many mining operations. Also, mechanical excavation and mining is more compatible with automation, meaning possibility of reduction in number of people in the active underground mines. This factor plays a major role in selection of mining systems especially considering the dire shortage of skilled labour in the industry. While these systems are an integral part of mining activities in underground soft rock mining (coal, salt, potash, trona etc.), there is a need for developing new approaches and machinery for use in the underground hard rock mining. This paper will offer a review of current and emerging technologies for mechanical hard rock excavation, including disc cutting technology, drag picks, mini-disc, and activated/oscillating disc cutter. A review of general guidelines for assessment of the potentials of new research and development on this topic and evaluation of emerging technologies for a specific mining application will also be offered.

The hilly terrain in Hong Kong is underlain by hard and massive igneous rocks. This brings favorable conditions to develop underground space including rock caverns as an alternative source of land supply. In recent years, the government departments have been playing a leading role to study the feasibility of rock cavern development in Hong Kong. These studies include the relocation of existing sewage treatment works, service reservoirs, refuse transfer stations, archive centre and laboratory to rock caverns. After completion of the relocation, the previously occupied surface land can be released for other developments beneficial to the communities. For an underground excavation in competent rock, the use of empirical design approaches is usually fast and straightforward to assess the rock mass conditions and determine the rock support systems. However, there are a number of limitations that empirical approaches cannot adequately address regarding the design of rock caverns, in particular the appropriateness for large-span excavation and influence of multiple parallel excavations.

Drill and blast method becomes unfavorable for deep mining of hard rock. Mechanical excavation with roadheader EBZ160TY was trialed at work face with hard rock and high ground stress. Work procedure and performance of the roadheader were recorded and analyzed. The results showed that, roadheader EBZ160TY, with designed excavating strength of 80 MPa, presented amazingly good performance in hard rock with strength of 148 MPa and consumed less cost compared to drill and blast method. High stress was found to play positive role in improving its working ability. Under the gentle disturbance of roadheader excavation, the high ground stress brings the surrounding rock mass to deform into yield and lets the stress/strain energy transform into fracture energy of rock fragmentation. With the push and rotation of roadheader, structural instability of confined high-stressed particle aggregate other than rock failure by mechanical wearing happens. The results show a good application prospect for roadheader in hard rock excavation especially at deep level.