Then, expressions of the contact force under various contact states were derived based on the explicit contact force algorithm, and a contact simulation method between blocks and the. Excavation support excavation for the diaphragm wall produces a vertical strip in. First a series of smalldiameter, ison 1997 parallel boreholes are drilled along the plane of the required final excavation boundary i. Mechanical underground excavation in rock springerlink. Support in hard rock underground mines 2 introduction rock support is the term widely used to describe the procedures and materials used to improve the stability and maintain the load bearing capacity of rock near to the boundaries of an underground excavation. Legally binding document step out from the old to the newjawaharlal nehru invent a new india using knowledge. In weak or very heavily jointed rock or in massive hard rock subjected to very high stress, failure of the rock mass. Types of underground excavation underground excavation design 3 bibl iography on underground excavations chapter 1 references chapter 2.
Tunnels and underground excavations, horizontal underground passageway produced by excavation or occasionally by natures action in dissolving a soluble rock, such as limestone. When considering the rock mass rating rmr values observed at the excavation face in six study cases, which. Failure process and stability analysis of rock blocks in a. Hoek and others published support of underground excavation in hard rock find, read and cite all the research you need on researchgate. It presents a variety of technical methods and data from diverse sources in the book, making it a valuable theoretical and practical reference resource for engineers, researchers and postgraduates alike. A method to estimate the pressure arch formation above. Underground excavations and structures rock chambers. Classification of rock masses introduction terzaghi s rock load classification classi fications by stini and lauffer oeeres rock qua lity designation rqo.
Rock excavation is required for all types of underground uses including mountain tunnels, mining operations, and large underground caverns where rock is at or near the surface. It is interesting to note that these systems, rqd, rmr and q system, have their origin in civil engineering. Udec modeling of an underground opening in rock masses. Knowledge of the magnitudes and directions of these in situ and induced stresses is an essential component of underground excavation design since, in many cases, the strength of the rock is exceeded and the resulting. Pillar and roof span design guidelines for underground.
This book deals with the geotechnical aspects of the design of underground openings for mining and civil. However, in nearsurface excavations, where the rock stresses are lower, the fractures more frequent, and the rock mass more disturbed and weathered, there is more concern about the validity of the chile model 5 of 37 erik eberhardt ubc geological engineering isrm edition. The procedure for excavation in rocks is different than excavation in ordinary soils. Naturally, prices for special quantities are higher than prices for general quantities.
Redesignated tm 58573 by da cir 31028, 17 march 1965. Approximate location of underground stone mines for which pillar and roof span dimensions, rock mass characteristics, and excavation stability conditions. Onecall centers, industry associations and magazines plus much more. This work resulted from close collaboration between industry and university in the fields of precompetitive research. University of rizona mining and geological engineering. Estimates were crew based and included an allowance for rock. Excavation is classified as common excavation, rock excavation, or unclassified excavation in accordance with the following definitions. Geological survey geological survey professional paper 965 a study to understand the effects of geology and rock stresses on. A trench or a trench excavation is a narrow excavation in relation to its length made below the surface of the. In this paper, a distinction is drawn between rock reinforcement or active support. It requires skilled manpower and specialized tools and equipments for excavating the rocky ground. Underground excavation design classification alfred zettler rock tunnelling quality index, q the first quotient rqdjn, representing the structure of the rock mass, is a crude measure of the block of particle size, with the two extreme values.
There are several classification systems used in underground mine design, however, most canadian mines rely on only one of three classification systems. Hoek,brown underground excavation in rock free ebook download as pdf file. Theory and technology of rock excavation for civil. It contains a number of worked examples to assist the reader in applying the techniques described to his or her own problems. Design of large underground caverns for hydroelectric projects with particular reference to structurally controlled failure mechanisms abstract two distinct types of failures occur in the roof and walls of excavations in rock. Excavation for the diaphragm wall in normal soil conditions excavation is done using a clamshell or grab suspended by cables to a crane. Support of underground excavations in hard rock is the most complete and uptodate manual for use in the design of excavations and support mechanisms for underground mines. Hoek and others published support of underground excavation in hard rock find, read and cite all the research. Support of underground excavations in hard rock is the most complete and.
Support of underground excavations in hard rock 1st edition by e. Underground excavations in rock 1st edition evert hoek. If rock excavation is required that is not indicated by the soils report, the walmart construction manager shall be notified prior to such rock excavation, and he must then visit the site and verify the necessity for excess rock excavation, determine an estimated quantity and provide the contractor written approval to proceed. Unanticipated rock deposits, special soil problems and. Estimating rmr values for underground excavations in a rock mass. Guideline for the geotechnical design of underground. The relation of geology to stress changes caused by. Price for excavation are for favorable working conditions. Defining excavation efficiency as the ratio between the sum of the times for drilling, charging, blasting and mucking operations, and the extended time when in line rock support activities are introduced into the excavation cycle, the efficiency may be expected to vary with tunnel size and the amount of support installed. Guideline for the geotechnical design of underground structures with conventional excavation austrian society for geomechanics 3 2 targets the main task of the geotechnical design is the economic optimization of the con. An excavation is any manmade cut, cavity, trench or depression in an earth surface, formed by earth removal. Support of underground excavations in hard rock mirarco. Design of large underground caverns for hydroelectric. Hoek,brown underground excavation in rock mining tunnel.
Too low rock stresses would lead to destressing in the country rock after excavation, while too high stresses would lead to rock failure due to stress concentration. The grab can easilyfchisel boulder in soil due to its weight. Hoek,brown underground excavation in rock free download pdf. If conditions such as rock formations, high water table or any other unforeseen problems requiring additional materials, time and labor, the responsible individual will be notified and any additional costs will be added to the invoice. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Excavation design in massive elastic rock is one of the simplest design problems in underground rock engineering. Technical manual design of underground insta llations in rock space layouts and excavation methods this is a reprint of former em 1110345433, 1 april 1961. At each mine, the excavation dimensions, rock jointing characteristics, rock mass classification, and excavation stability conditions were recorded. This work resulted from close collaboration between industry and university in the.
Underground excavation in crystalline rocks at idaho springs, colorado by fitzhugh t. Mechanical methods for underground excavation have the most advantage of less disturbance to the surround environment, especially in the urban area and complex ground conditions. Ge 33ab engineering analysis of underground rock excavation school of civil and environmental engineering 20. Estimating excavation revised craftsman book company. Code of practice for construction of tunnels, part ii. Basic knowledge, surface excavation and underground excavation.
Though the basic concept originated in the united states, where the worlds first underground hydroplants were built in enlarged tunnels at snoqualme falls. The two thrusts of this study were to 1 document qualitative correlation between rmr ratings and behavior of the rock mass, and 2 investigate the dimensions of the unstable zone that develops around the excavation. Ask the utility companies or owners to establish the location of underground installations prior to the start of excavation work. In historic times, rock excavation was painfully slow, relying on hand tools or even thermal shock 3 to disintegrate the rock. Reinforcement of underground excavation with expansion shell rock bolt equipped with deformable component 41 fig. The osha underground construction regulation 29 cfr 1926. Scribd is the worlds largest social reading and publishing site. Keeping these two quantities separate protects you. Note the fxx is used for the ordinate of a pdf while fxx is used for a cdf. Reviewed in the united states on november 18, 2006.
This includes the trenching and excavation requirements of 29 cfr 1926. Excavation in rock requiring drilling and blasting shall be done under coordination of competent and responsible supervision. It also applies to cutandcover excavations connected to ongoing underground construction as well as those that create conditions characteristic of underground construction. Rock mass characterization for underground hard rock mines. Arching effect has also been perceived in surrounding rock with underground excavations development. Rock mass characterization is an integral part of rock engineering practice. First, a mesh model that includes marked blocks was established based on the gridbased block identification method. Read underground engineering for sustainable urban. A numerical analysis method for block failure is proposed that is based on continuum mechanics. While chambers in 1971 were being excavated in rock to fulfill a wide variety of functions, the main stimulus to their development had come from hydroelectricpowerplant requirements. Hoek is probably currently the master of rock mechanics having not only invented many applied theories including hoekbrown criteria but also being a well known international consultant. The type of excavation disturbance is mainly associated with the magnitudes of the in situ stresses with respect to the quality of the rock mass. Most excavation contracts have a clause that covers extra work.