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Swelling soils. Technical note
355A dimensions and in Laplace and real-time domains. A boundary integral equation is also presented and an illustrative example examined in order to demonstrate the influence of full coupling on the field quantities.
936178 Swelling soils. Technical note Sikh, T S J Geotech Engng Div ASCE Vl19, N4, April 1993, P791-792 One dimensional unrestrained swell tests under 6.9kPa pressure were carried out on relatively undisturbed soil samples taken with the modified California sampler. The soils were mainly from existing fills of predominantly montmorillonitic clay with some sand. Results have been correlated with in situ measurements of near surface swelling pressures. The correlation can prove useful in making preliminary estimates of swelling pressure if free swell is known, or vice versa.
936179 Evaluation of in-place wetting using soil suction measurements Walsh, K D; Houston, W N; Houston, S L J Geotech Engng Div ASCE V119, N5, May 1993, P862-873 Following distress to a structure on deep collapsible soil deposits, an evaluation of water sources and extent of wetting was undertaken. The underlying soils were highly variable in fines content, density, and saturation. Suction contours were determined to evaluate the extent of soil wetting, using a specially developed relation between suction and basic soil parameters. Estimated depth of wetting from these contours was consistent with other data for the site, including quantity of water introduced and SPT results. Laboratory collapse curves using inferred depth of wetting predicted settlements consistent with those observed.
936180 Ultimate settlement by hyperbolic plot for clays with vertical drains. Technical note Tan, S A J Geotech Engng Div ASCE Vl19, N5, May 1993, P950-956 The rectangular hyperbola method (time factor/degree of consolidation vs time factor) is examined to see at what range the consolidation settlement record for infinitesimal strain actually converges to the linear hyperbolic plot. Both vertical flow and combined vertical-horizontal flow (vertical drains with surcharge) cases are considered. The study is validated against field data from a long term loading test of clay deposits with vertical sand drains.
936181 Conical test load measuring compressibility. Technical note Schmertmann, J H J Geoteeh Engng Div ASCE Vl19, N5, May 1993, P965-971 The conical test load (CTL) method involves construction of a cone-shaped mound of soil on the ground over a centre plate and measuring the induced settlement of the plate. The compressibility of the underlying soil layers can be calculated using the settlement data. The concepts of the simple, inexpensive method and its advantages are presented. Field data are used to demonstrate its practicality.
936182 Quasi-preconsolidation effects developed in normally consolidated clays. Technical note Murakami, Y Soils Found 1132, N4, Dec 1992, P171-177 When normally consolidated clays which have undergone secondary compression are loaded, a threshold pressure is reached before particle sliding begins. This is termed the quasi-
preconsolidation effect and can mostly be explained using Bjerrum's concept considering delayed compression of clay. The differences between observed and estimated quasi-preconsolidation pressure are discussed with reference to laboratory test data. Degree of difference is influenced by duration of sustained loading at some previous stage and to some extent by soil properties, but not by consolidation pressure.
936183 Deformation of earth dams due to rise of water level Yin, Z Z; Zhang, J F Proc Ninth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Bangkok, 9-13 December 1991 V1, P453-456. Publ Thailand." Southeast Asian Geotechnical Society, 1991 Rockfill and earthfill dams will undergo wetting deformation on first filling. Two methods are available to assess wetting deformation, direct measurement of wetting deformation of a sample undergoing saturation at a given stress level, or testing wet and dry samples and taking the difference in strains as wetting deformation. Both methods are described and discussed. An empirical formula is proposed to modify the indirect measurements to increase accuracy and is used successfully in preliminary examination of an earth dam.
936184 Stability of the Olga C test embankment Lavallee, J G; St-Arnaud, G; Gervais, R; Hammamji, Y Proc Conference Stability and Performance of Slopes and Embankments II, Berkeley, 29 Jane-1 July 1992 112, P10061021. Publ New York: ASCE, 1992 (ASCE Special Geotechnical Publication No 31) The Olga C test embankment was built to enable the performance of wick drains in soft sensitive clay deposits to be checked before use in construction of retaining structures up to 25m high in Quebec. Undrained shear strength gain was measured after a period of 10 months, when most of the primary settlement due to consolidation had occurred. No signs of instability were seen. Horizontal displacements were limited to only a few centimetres.
936185 Application of the analysis of microscopic features of weak rocks in underground openings Xin Yumei; Zhong Weilin; Wen Xuehan Proe 26th Annual Conference of the Engineering Group of the Geological Society, The Engineering Geology of Weak Rock, Leeds, 9-13 September 1990 P95-99. Publ Rotterdam: A A Balkema, 1993 (Engineering Geology Special Publication No. 8) Silt-bearing montmorillonitic mudstone from the roof of the No 2 seam of the Beizao coal mine in Shandong Province, China, has been examined in the laboratory. Transmission and scanning electron microscopy were used to establish microstructure and mineralogy. Swelling of the rock due to water absorption perpendicular and parallel to stratification under unloading conditions has been studied and the mechanism of swelling determined. Based on this work, advice is given on mine layout and mining practices to minimise problems due to roof rock swelling.
© 1993 Pergamon Press Ltd. Reproduction not permitted
936178 Swelling soils. Technical note Sikh, T S J Geotech Engng Div ASCE Vl19, N4, April 1993, P791-792 One dimensional unrestrained swell tests under 6.9kPa pressure were carried out on relatively undisturbed soil samples taken with the modified California sampler. The soils were mainly from existing fills of predominantly montmorillonitic clay with some sand. Results have been correlated with in situ measurements of near surface swelling pressures. The correlation can prove useful in making preliminary estimates of swelling pressure if free swell is known, or vice versa.
936179 Evaluation of in-place wetting using soil suction measurements Walsh, K D; Houston, W N; Houston, S L J Geotech Engng Div ASCE V119, N5, May 1993, P862-873 Following distress to a structure on deep collapsible soil deposits, an evaluation of water sources and extent of wetting was undertaken. The underlying soils were highly variable in fines content, density, and saturation. Suction contours were determined to evaluate the extent of soil wetting, using a specially developed relation between suction and basic soil parameters. Estimated depth of wetting from these contours was consistent with other data for the site, including quantity of water introduced and SPT results. Laboratory collapse curves using inferred depth of wetting predicted settlements consistent with those observed.
936180 Ultimate settlement by hyperbolic plot for clays with vertical drains. Technical note Tan, S A J Geotech Engng Div ASCE Vl19, N5, May 1993, P950-956 The rectangular hyperbola method (time factor/degree of consolidation vs time factor) is examined to see at what range the consolidation settlement record for infinitesimal strain actually converges to the linear hyperbolic plot. Both vertical flow and combined vertical-horizontal flow (vertical drains with surcharge) cases are considered. The study is validated against field data from a long term loading test of clay deposits with vertical sand drains.
936181 Conical test load measuring compressibility. Technical note Schmertmann, J H J Geoteeh Engng Div ASCE Vl19, N5, May 1993, P965-971 The conical test load (CTL) method involves construction of a cone-shaped mound of soil on the ground over a centre plate and measuring the induced settlement of the plate. The compressibility of the underlying soil layers can be calculated using the settlement data. The concepts of the simple, inexpensive method and its advantages are presented. Field data are used to demonstrate its practicality.
936182 Quasi-preconsolidation effects developed in normally consolidated clays. Technical note Murakami, Y Soils Found 1132, N4, Dec 1992, P171-177 When normally consolidated clays which have undergone secondary compression are loaded, a threshold pressure is reached before particle sliding begins. This is termed the quasi-
preconsolidation effect and can mostly be explained using Bjerrum's concept considering delayed compression of clay. The differences between observed and estimated quasi-preconsolidation pressure are discussed with reference to laboratory test data. Degree of difference is influenced by duration of sustained loading at some previous stage and to some extent by soil properties, but not by consolidation pressure.
936183 Deformation of earth dams due to rise of water level Yin, Z Z; Zhang, J F Proc Ninth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Bangkok, 9-13 December 1991 V1, P453-456. Publ Thailand." Southeast Asian Geotechnical Society, 1991 Rockfill and earthfill dams will undergo wetting deformation on first filling. Two methods are available to assess wetting deformation, direct measurement of wetting deformation of a sample undergoing saturation at a given stress level, or testing wet and dry samples and taking the difference in strains as wetting deformation. Both methods are described and discussed. An empirical formula is proposed to modify the indirect measurements to increase accuracy and is used successfully in preliminary examination of an earth dam.
936184 Stability of the Olga C test embankment Lavallee, J G; St-Arnaud, G; Gervais, R; Hammamji, Y Proc Conference Stability and Performance of Slopes and Embankments II, Berkeley, 29 Jane-1 July 1992 112, P10061021. Publ New York: ASCE, 1992 (ASCE Special Geotechnical Publication No 31) The Olga C test embankment was built to enable the performance of wick drains in soft sensitive clay deposits to be checked before use in construction of retaining structures up to 25m high in Quebec. Undrained shear strength gain was measured after a period of 10 months, when most of the primary settlement due to consolidation had occurred. No signs of instability were seen. Horizontal displacements were limited to only a few centimetres.
936185 Application of the analysis of microscopic features of weak rocks in underground openings Xin Yumei; Zhong Weilin; Wen Xuehan Proe 26th Annual Conference of the Engineering Group of the Geological Society, The Engineering Geology of Weak Rock, Leeds, 9-13 September 1990 P95-99. Publ Rotterdam: A A Balkema, 1993 (Engineering Geology Special Publication No. 8) Silt-bearing montmorillonitic mudstone from the roof of the No 2 seam of the Beizao coal mine in Shandong Province, China, has been examined in the laboratory. Transmission and scanning electron microscopy were used to establish microstructure and mineralogy. Swelling of the rock due to water absorption perpendicular and parallel to stratification under unloading conditions has been studied and the mechanism of swelling determined. Based on this work, advice is given on mine layout and mining practices to minimise problems due to roof rock swelling.
© 1993 Pergamon Press Ltd. Reproduction not permitted