Coal ash as structural fill, with special reference to Ontario experience

173A vacuum testing. Limitations of the test due to large soil particle size or heterogeneous materials are considered. Although test results are indicative of in situ behaviour, most failures occur during initial construction. 894029 Flow behaviour of allophane and ferrihydrite under shearing forces Wells, N; Childs, C W Aust J Soil Res V26, NI, 1988, P145-152 AIIophane and ferrihydrite impart major physical and chemical characteristics to soils derived from weathered volcanic ashes. Undisturbed samples were sheared between cone and plate in a rotary type viscometer. During rotor acceleration, both developed maxima of shear stress that did not re-establish on deceleration. A sudden loss of strength indicated sensitivity to shearing forces. The minerals were then tested as pastes at various moisture contents. Results show sensitivity to shear and lack of strength in the disturbed state, which has implications for soil engineering. 894030 Coal ash as structural fill, with special reference to Ontario experience Toth, P S; Chan, H T; Cragg, C B Can Geotech J V25, N4, Not' 1988, P694-704 A summary of the engineering properties of fly ash, including grain size and particle shape, compaction, specific gravity, shear strength and hydraulic conductivity, is presented. Four case studies of fly ash used as structural fill are presented, showing that physical behaviour is similar to that of silt, and structural fill of fly ash performs as well as or better than fill constructed of silt sized natural materials with respect to ease of compaction and settlement. Two studies of fly ash landfill sites monitored groundwater quality due to ash leachate migration, and indicated there would be no detrimental effect on buried services or good quality concrete structures. 89403 I Viscosity, yield stress, remolded strength, and liquidity index relationships for sensitive clays Locat, J; Demers, D Can Geotech J V25, N4, Not, 1988, P799-806

894033 Empirical failure criterion for rocks and jointed rock masses Sheorey, P R; Biswas, A K; Choutxy, V D Engng Geol V26. N2. Jan 1989, P141-159 A new triaxial strength equation has been developed using data from a number of triaxial tests. It is shown that the 5 triaxial parameters - unconfined compressive, tensile and shear strengths, coefficient of friction and exponent in the triaxial equation - can be interrelated by 3 equations. A relation between intact rock strength/rock mass strength ratio and Barton's rock quality is next developed based on geomechanical data for four longwall panels and in situ coal strength data. Performance of the failure criterion is studied using practical cases of rock structures in coal and coal measure strata. Auth. 894034 Geotechnical properties of fine-grained calcareous sediments for engineering purposes Qahwash, A A Engng Geol V26, N2, Jan 1989, P161-169 The geotechnical properties of the mar[ of the DammamDhahran area, both alone and mixed with various proportions of sand, were determined. Grain size distribution, plasticity, specific gravity, compressibility and California Bearing Ratio (CBR) were obtained. Results show that increase in sand content increases maximum dry density and CBR and decreases optimum moisture content. 894035 Some engineering properties of stabilized salina soil Stipho, A S Engng Geol V26, N2, Jan 1989, P181-197 Tests were undertaken to study the effectiveness of soil treatment methods on the engineering properties of salina soils, which vary according to salt type and moisture content. In one test, the coarser grained coastal soils were treated with Portland cement and the effect on shear strength, compactibility, cone penetration resistance and bearing capacity considered. In the second test, the finer grained inland soil was treated with unhydrated lime and the effect on consistency limits, permeability, compaction, shearing resistance, bearing capacity and linear shrinkage analysed. 894036 Estimation of in situ strength of weak sandstones. Technical note Glynn, M E lnt J Man Geol Engng V6, N3, Oct 1988, P273-278

Viscometric tests were undertaken on 6 clay samples covering a range of plasticity indices, sensitivity and clay fraction. The tests were of 3 types, dynamic response, constant shear rate and hysteresis. Testing consisted of: (I) determination of geotechnical parameters; (2) slowly increasing liquidity index, but maintaining pore water salinity; (3) viscometric testing after each water increase; and (4) determination of remolded undrained shear strength. The clays showed good correlation between liquidity index, viscosity and remolded shear strength. Changes in salinity of pore water affect remolded shear strength, viscosity and yield stress.

Calcareous fanglomerates are gravelly sands which show the characteristics of weak sandstones, being continuously cemented, and having few discontinuities or fissures and high relative density. Undisturbed samples are rare, so in situ strength is determined from sonic velocity tests, assuming a relation between computed dynamic modulus and strength. Data show good agreement with back analysis and limited plate test data.

894032 Penetration resistance to characterize the depth and persistence of soil loosening in tillage studies Carter, M R Can d Soil Sci V68, N4, Not" 1988, P657-668

894037 Shear properties of fragmented rock masses - model tests and theories Forsman, B; Pan, C L int J Rock Meek Man Sci 1:26, NI, Jan 1989, P25-36

The penetration resistance of fine sandy loam soils was studied to determine depth, degree and persistence of soil loosening under different tillage systems. A recording penetrometer was used to determine resistance when water content was near field capacity.

Factors influencing the shear strength of fragmented rock were studied to give a better theoretical background for developing rock loading techniques. Shear tests were carried out on 3 specimen types to determine the influence of particle size distribution, moisture content and compaction on shear strength

1989 Pergamon Press plc. Reproduction not permitted