Application of holographic interferometry to in-situ stress measurement

Application of holographic interferometry to in-situ stress measurement

231A Measurement of in situ stress See also. ,~'6632l 866138 Factors affecting the performance of a pneumatic earth pressure cell. Technical note Fe...

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231A

Measurement of in situ stress See also. ,~'6632l

866138 Factors affecting the performance of a pneumatic earth pressure cell. Technical note Felio. G Y: Bauer. G E Geotech Test J 1"9, N2, June 1986, P102-106 The performance of 20 pneumatic earth pressure transducers installed at a bridge abutment was found to be significantly affected by temperature and to a lesser extent by the type of soil in contact and the installation procedure. Extensive laboratory studies were undertaken to quantify these effects and suitable correction factors ,,,,ere obtained and have been applied to field data.

866 ! 39 Diametral deformation method for in situ stress and rock property measurement Serata, S: Kikuchi, S Int J Min GeM Engng 1"4. NI, March 1986, PI5-38 The diametrat deformation method of stress measurement described was developed to overcome the difficulties inherent in both conventional methods, ovcrcoring and hydrofractt, ring. The method was first developed by means of finite clement simulation models and confirmed by laboratory model studies. It wits ficld tested in an outcropping of homogeneous sandstone and latcr applied to three underground geological formations: highly stratified shale, rock salt and fractured green schist. Some of these results are presented to illustrate the method's ,,alidit> and usefulness, especially in complex ground The instrumentation involves a borehole probe which utilizes electrically powered hydraulic pumping, and computerized data acqt.isition l\~r rapid measurement and on-site analysis. The significance of the new method is its ability to obtain input data of in situ stress states and material propertics for finite element analysis of earth structures in complex ground.

866140 Application of holographic interferomctry to in-situ stress measurement Schmitt. D R; Bass. J D: Ahrcns. T J In: Research and Engineering Applications in Rock Alasses (paper to the 26th US Symposium on Rock Mechanics, Rapid City, 26-28 Jane 1985) 1"2. P1055-1056. Puhl Rotters&m: A. A. Balkema. 19,~'5 A borehole stress meter which records stress-relict" displacements via double exposure holography is under development. It records a three dimensional displacement field resulting from the drilling of a small stress relieving hole in the borehole `,`,all. Data is stored in the form of a fringe pattern superimposed on the image of the borehole wall and the stress relief hole. 866141 Problems associated with near surface in-situ stress measurements by the overcoring method Garritty. P; lrvin. R A: Farmer, I W in: Research and Engineering Applications in Rock Masses (paper to the 26th US Symposium on Rock Alechanics, Rapid City, 26-28 Jane 1985) I'2, P1095-1102. Putq Rotterdam: A. A. Balkema. 1985 The errors arising when measuring geostatic stress by overcoring have bccn studied for the CSIRO hollow inclusion gauge. a solid inclusion cell.a modified Lecman cell and the USBM

gauge. Errors from instrumental, en,,ironmental and testing sources are examined. When geostatic stress is Io`,`,, errors may cause strains in excess of those from overcoring relief. A method of measuring these errors has been de',cloped and used with success.

Site Investigation and Field Observation See:866266, 866298

Remote sensing and photographic techniques 866142 Early regional photointerpretation and geologic studies of landslide terrain along the Saskatchewan and Qu'Appelle River valleys. Note Mollard. J D Can Geotech J V23, NI. Feb 1986, P79-83 The importance of interrektting site investigation, geology, and airborne photography was first demonstrated in the 1950s, when landforms at dam abutments wcre correctly identified as landslide masses, not ht, mn~ocky morainal material. In the 1980s, more sophisticated remote sensing techniqt.es and increased basic knowledge arc a`,ailable to approach to the new problems facing geotechnical engineers.

866143 Stereographie mapping technique Rorkc, A J; Brummcr, R K Proc ~" the S.rmposium on Rock Mass Characterization, Randburg, South Africa, 8 Nov 1985 P117-119. Pull South ,.{lrica:ISRM. 19,~5 A method using stereophotography is described for mapping highly fractured rock surfaces accurately and fast. Large areas of 50 to 100 sq m can be photographed in less than 10 hours. A numerical mapping tcchniqtte is used for correcting distortions on the images rest.lting from inconsistency in camera orientation and position relative to the surfaces being mapped. The method hits been used successfully in the understanding of mining induced fracturing around stopes. Auth.

Geophysical techniques 8661'44 Evaluation of electrical resistivity methods in the investigation of karstic features, El Cajon dam site, Honduras Smith, D L: Randazzo, A F Engng Geol V22. N3. April 1986, P217-230 A report describing the use of different methods of obtaining electrical resistivity measurements to detect subsurface cavities and clay pockets at a Honduran dam site. The purpose of this investigation was to determine the presence and size o[" any air-filled or clay-filled dissolution voids below the valley floor immediately upstream from the dam site. Wenner, Schlumberger, and Bristow (pole-dipole) array configurations of electrical resistivity measurements were used to detect the presence of subsurt:ace dissolution features. The best results v,erc obtained from Schlumbcrger and Bristou, array configurations. Several zones of anomalously high resistivity were detected. Subsequent drilling confirmed the presence of subsurface dissolution featurcs v, hich could ha',e seriously jeopardized the dam.

~' 1986 Pergamon Journals Ltd. Reproduction not permitted