Rock Stress Measurements Research Articles

Field stress measurements in jointed rock : Obara, Y; Sugawara, K Proc International Conference on Mechanics of Jointed and Faulted Rock, Vienna, 18–20 April 1990P827–834. Publ Rotterdam: A A Balkema, 1990

Field stress measurements in jointed rock : Obara, Y; Sugawara, K Proc International Conference on Mechanics of Jointed and Faulted Rock, Vienna, 18–20 April 1990P827–834. Publ Rotterdam: A A Balkema, 1990

Experimental measurement of rock stress to assess the stability of stope mining (In Italian and English) : Gallerie V13, N35, 1991, P23–38

Experimental measurement of rock stress to assess the stability of stope mining (In Italian and English) : Gallerie V13, N35, 1991, P23–38

Hydraulic fracture stress measurements in rocks with stress-dependent Young's Moduli

Hydraulic fracture stress measurements in rocks with stress-dependent Young's Moduli

Scale effects in rock mass stress measurements

Abstract The First International Workshop on Scale Effects in Rock Masses was held in Loen, Norway in 1990. The current state of knowledge on scale effects in rock stress measurements, as reflected in the workshop proceedings is summarized in this paper. One type of scale effect is inherent in the rock structure due to heterogeneities ranging from micro- to macro-scale. A second scale effect is involved through the scale of application considered. The implications of these scale effects are discussed. Emphasis is placed on consequences for stress measurement design.

A comparison of hydraulic measuring techniques for borehole rock stress measurements

A comparison of hydraulic measuring techniques for borehole rock stress measurements

Stabilizing and stability control of a cave-prone area in the Tverrfjellet mine, Norway

In the Tverrfjellet Mine, mid Norway, serious stability problems have developed in connection with large open mining stopes. The problems may be related to high in situ horizontal rock stresses combined with unfavourable geometry. To stabilize the most critical area cable bolting has been used. Closely associated with the stabilizing measures is a caving warning system based upon eight borehole extensometers. Deformations in the rock mass in excess of 1 mm on any one of the extensometers will trigger red stop lights in vital haulageways passing through the threatened area. In the most critical area the deformation is continually monitored. About 1 ½ yr of operation have shown a steady decrease in deformation rate, indicating that the cable bolting works as planned. However, small deformations still take place, necessitating keeping the warning system operative until new by-pass haulageways are established. The rock mechanics program in the mine also includes rock stress measurements and monitoring of stress change. A modified version of the doorstopper used for stress change monitoring has proved very promising.

Scale effects in rock stress measurements : Haimson, B C Proc 1st International Workshop on Scale Effects in Rock Masses, Loen, 7–8 June 1990P89–101. Publ Rotterdam: A A Balkema, 1990

Scale effects in rock stress measurements : Haimson, B C Proc 1st International Workshop on Scale Effects in Rock Masses, Loen, 7–8 June 1990P89–101. Publ Rotterdam: A A Balkema, 1990

Measurement of rock stress using the hydraulic fracturing method in Cornwall, U.K. - Part II. Data reduction and stress calculation : Haimson, B C; Tunbridge, L W; Lee, M Y; Cooling, C M Int J Rock Mech Min Sci V26, N5, Sept 1989, P361–372

Measurement of rock stress using the hydraulic fracturing method in Cornwall, U.K. - Part II. Data reduction and stress calculation : Haimson, B C; Tunbridge, L W; Lee, M Y; Cooling, C M Int J Rock Mech Min Sci V26, N5, Sept 1989, P361–372

Measurement of rock stress using the hydraulic fracturing method in Cornwall, U.K. — Part I. Field measurements : Tunbridge, L W; Cooling, C M; Haimson, B C Int J Rock Mech Min Sci V26, N5, Sept 1989, P351–360

Measurement of rock stress using the hydraulic fracturing method in Cornwall, U.K. — Part I. Field measurements : Tunbridge, L W; Cooling, C M; Haimson, B C Int J Rock Mech Min Sci V26, N5, Sept 1989, P351–360

Hydrofracturing stress measurements in fractured rock. A laboratory study : Rock Mechanics as a Guide for Efficient Utilization of Natural Resources: Proc 30th U.S. Symposium, Morgantown, 19–22 June 1989P427–434. Publ Rotterdam: A A Balkema, 1989

Hydrofracturing stress measurements in fractured rock. A laboratory study : Rock Mechanics as a Guide for Efficient Utilization of Natural Resources: Proc 30th U.S. Symposium, Morgantown, 19–22 June 1989P427–434. Publ Rotterdam: A A Balkema, 1989

Measurement and monitoring of rock stress by means of flatjack, pressure capsule and hydraulic fracturing techniques at Yanahara mine : Ogino, S; Mizuta, Y; Sano, O; Araki, H Proc 2nd International Symposium on Field Measurements in Geomechanics, Kobe, 6–9 April 1987V1, P105–114. Publ Rotterdam: A A Balkema, 1988

Measurement and monitoring of rock stress by means of flatjack, pressure capsule and hydraulic fracturing techniques at Yanahara mine : Ogino, S; Mizuta, Y; Sano, O; Araki, H Proc 2nd International Symposium on Field Measurements in Geomechanics, Kobe, 6–9 April 1987V1, P105–114. Publ Rotterdam: A A Balkema, 1988

Application of small-scale hydraulic fracturing for stress measurements in bedded salt

In situ rock stress measurements by small-scale hydraulic fracturing were performed in two salt beds in the Texas Panhandle, approximately 60 km (36 miles) south of Amarillo, Texas. Data analysis indicates that small-scale hydraulic fracturing is applicable for determining the magnitude of the minimum principal stress and the direction of the maximum stress in salt. However, when hydraulic fracturing equations based on elasticity are applied to salt (a non-elastic medium), anomalously high in situ maximum stress and tensile strength values are calculated. Due to the non-elastic properties of salt and it's solubility, neither the derived maximum stress nor the tensile strength values are considered valid using the elastic hydraulic fracturing stress equations.

Measurement of rock stress using the hydraulic fracturing method in Cornwall, U.K.—Part II. Data reduction and stress calculation

Data from two series of hydraulic fracturing experiments at the Carwynnen test site were used to estimate the state of in situ stress in the Cornwall granite. We discuss several techniques of pressure record interpretation, and alternate methods of in situ stress calculation.

Measurement of rock stress using the hydraulic fracturing method in Cornwall, U.K.—Part I. field measurements

The equipment and test methods used to determine the in situ stress by the hydraulic fracturing method are described. A programme of trials in boreholes down to 700 m in granite in Cornwall, U.K. was undertaken and the test methods used are outlined. The performance of the equipment is evaluated and possible improvements to the system are discussed.

Rock stress measurements in the Grimsel Underground Rock Laboratory and their geological interpretation

Rock stress is being studied as part of the Swiss-German cooperation between the National Cooperative for the Storage of Radioactive Waste (NAGRA), the Research Centre for Environmental Sciences (GSF), and the Federal Institute for Geosciences and Natural Resources (BGR) in the Grimsel Rock Laboratory in Switzerland. Several methods and various equipment for measuring rock stress have been developed and tested in an approximately 200-m borehole drilled from a gallery at a depth of 450 m. The measurements were made continually during overcoring; the data were recorded and processed in a computer located downhole or outside the borehole. The results of the overcoring tests and of frac tests indicate a principle horizontal stress of 25–40 MPa, directed mainly NW-SE. Detailed geological mapping shows relationships between stress and rock structure. A zone of nearly unfractured rock exhibits an increase in stress and a change in stress direction.

Relevance of pointwise rock stress measurements — an analysis of overcoming data : Leijon, B A Int J Rock Mech Min SciV26, N1, Jan 1989, P61–68

Relevance of pointwise rock stress measurements — an analysis of overcoming data : Leijon, B A Int J Rock Mech Min SciV26, N1, Jan 1989, P61–68

Bolmen project: rock stress measurements using hydraulic fracturing and overcoring techniques : Bjarnason, B; Leijon, B; Stephansson, O Tunnlg Underground Space TechnolV3, N3, 1988, P305–316

Bolmen project: rock stress measurements using hydraulic fracturing and overcoring techniques : Bjarnason, B; Leijon, B; Stephansson, O Tunnlg Underground Space TechnolV3, N3, 1988, P305–316

韓国，鳳鳴炭鉱と大成炭鉱における岩盤応力の測定

韓国，鳳鳴炭鉱と大成炭鉱における岩盤応力の測定

Rock mechanics in Sweden

This paper reviews rock mechanics research activities in Sweden. A short history of the development of rock mechanics in the mining, underground construction and mining equipment industries is presented. Teaching at Swedish technical universities and activity in research organizations and in the Swedish National Group of the ISRM are outlined. The relatively young science of rock mechanics is now recognized in the Swedish scientific community and there is a growing interest in and demand for research activity. For the next 5–10 yr, most of the applied rock mechanics research will be conducted in the fields of mining and the final disposal of radioactive waste. New fields in the application of rock mechanics are being developed, for example, gas storage in excavations of hard rocks. Tunnel boring in hard rocks, holography for rock monitoring during blasting, physical and numerical modelling of grouting and some new trends in rock stress measurements are presented as examples of present research work within the major research organizations and university departments in Sweden.

Relevance of pointwise rock stress measurements—an analysis of overcoring data

Application of in situ rock stress data to analysis of rock engineering problems often requires prediction of the in situ stress distributions within large rock masses, on the basis of point observations. In this paper, a number of fundamental difficulties associated with the procedures used for these predictions are illustrated. The interpretation of stress measurements obtained from multiple sampling along borehole sections with lengths of the order of 10 m is discussed. An analysis of critically selected data from triaxial overcoring tests is presented. The data originates from 10 sites, all located in hard rock formations within Sweden. It is shown that if the test points along a borehole are separated by distances of the order of 1 m, the results from neighbouring points are not serially uncorrelated. Furthermore, it is concluded that local variations of the order of ±20% in Young's modulus cannot be correlated to measured variations in the in situ, mean stress or mean strain. The random measuring error in the data obtained, expressed as a standard deviation in the mean stress, is found to be ±2 MPa or less. The in situ variation of the mean stress, expressed as a relative standard deviation is 5–20% over distances of about 10 m. This value is relative to stress magnitudes larger than about 15 MPa.