Applied Mechanics and Materials Vols. 405-408

Abstract: The paper set an example of high antidip sandwich rock slope to study its creep and fracturing deformation in high in-situ stresses at Jinping First Stage Hydropower Station in China. The slope creep deformation before and after excavation could be found on slope face and in exploration adits. Displacements at 4 monitoring points on the slope were abnormal for influences of fault f_42-9, zone SL_44-1 and lamprophyre dike, which indicate creep and fracturing of the big block separated by them. Through stereographic projection analysis, intersection of controlling structural planes of the big block direct outside the slope. Its bottom slide face, fault f42-9, has internal friction angle smaller than depression angle of the intersection line. Barricade in front of the big block removed by slope excavation decreased resistance to slope slide. It is concluded that creep and fracturing deformation of the big block is controlling stability of the slope.

Abstract: Karst caves determine the engineering characteristics of the whole rock in a large extent. A methed to simulate karst caves is described in this paper. Firstly, three-dimensional mathematic description of the geological mass in which karst caves lies is given. Secondly, the determination of the shape and size of ellipsoids which are adopted to simulate karst caves is introduced in detail. The mathematic modeling of three-dimensional random caves is discussed simultaneously. Thirdly, a real three-dimensional random structural model of karst rock based on actual observation records is provided. Lastly, the above model used for the leakage analysis of the karst rock is discussed. The research results illustrates that the Mathematic model for three-dimensional random caves of karst rock put forward in this paper can be very helpful to leakage analysis on Karst rock.

Abstract: This paper presents a new mechanism for loess self-load Collapsibility-saturated loess liquefaction caused by earth microtremors .The principle of earth microtremors is briefly introduced and the processes of saturated loess liquefaction induced by earth microtremors are analyzed from a dynamic view. A field test of loess in water immersion was done over a 420 hour period on Gaolanshan Mountain at Lanzhou,China. After stopping water flooding, earth microtremors at the bottom of test impounding pits were continuously measured by seismic equipment.We conclude that there is a relationship between loess collapsing values and the amplitude and predominant period of the earth microtremors.The results of our study show that the higher the amplitude and the longer the predominant period of earth microtremors, the more intensive will be the liquefaction grade.Finally,then most probable series of affecting factors to liquefaction,such as C. values of loess,amplitude, frequency, duration,wave type and propagation direction are all favorable to loess liquefaction.

Abstract: The compaction characteristics of the lime-treated expansive soils from the planning airport in China's Ankang were studied through the heavy compaction tests. The results show that all these elements such as lime content, water content, soil height, wetting time have a certain effect on dry density. As the lime quality ratio increases, the optimum water content under heavy compacting standard of improved soils increases but the maximum dry density decreases. With the increase of lime content, the effect of water content on dry density decreases while the water content near to its optimum value. Soils with the lower height have higher dry density when compaction energy, lime content and water content unchanged. As the wetting time increases, the maximum dry density shows a decreasing tendency until after 48 h it remained stable. It indicates that with the same lime content the order of primary factors influence on dry density are water content, wetting time, soil height. Finally, the lime stabilizing principle to expansive soil is explained through by applying scanning electron microscope technique.

Abstract: The landslide is one of common geological disasters, and it brought about enormous damages to the society. Taking Meng Dumei landslide in Jilin Province for example, cutting slope and filling earth counter pressure were applied in the landslide treatment based on the stability analysis in GeoStudio. The results shows that the landslide is under stable state when the thickness of cutting slope is 28m. This method was shown to be effective and economic on the premise of safety.

Abstract: Since a long time of excavation, the slope in Yang-mountain of Suzhou Province became a high and steep slope which has 260m difference in height, on top of this slope there is a high risky cataclastic texture bedrock landslide. Based on geologic investigation of the landslide, combined with 3DEC numerical simulation, the paper gave a comprehensive analysis on formation precondition, evolution procedure, failure model and mechanism from the points of topographic feature, structure evolution history, lithology and external influence. It is shown that the free face in front of the landslide, weak quartz porphyry dike in front of the sliding zone, cataclastic rock structure formed by nappe structure are the main factors which control the formation and failure mode of the landslide.

Abstract: M coal mine is located in the hilly terrain of mountain front in the southern margin of Junggar Basin in Fukang. The geological structure belongs to a medium type in the mine area where there are surface faults (two larger faults) and structural developments. The stratigraphic dips of south limb of Fukang syncline and southern Fukang anticline are large while that near F5 fault of anticline axis are larger and even upright. Brittle rocks develop fractures. In consideration of meteorology, earthquakes and other factors, mining may lead to such geological hazards as eboulement and surface subsidence, which should be highlighted.

Abstract: With hydrochloric acid as the source of pollution, with laterite as the pollution soil, the shear strength and micro-structural characteristics of acid pollution laterite are studied by direct shear test. The results shown that, the shear strength and microstructure characteristics of acid pollution laterite are affected acid concentration and pollution time. The shear strength and indexes of acid pollution laterite decrease in general with the increase of acid concentration and the extension of the specimen pollution time, the shear strength and indexes exist a minimal value at lower concentration and shorter pollution time, the shear strength and indexes exist a great value at higher concentration and longer pollution time, the corresponding microstructure images present to the characteristics of compactness, roughness, color, texture.

Abstract: Permeability coefficients of three compacted clay samples are measured by using Transient Water Release and Imbitions Method which is shortly named as TRIM. The curve between permeability coefficient and suction is obtained, the results of tests show that the permeability coefficient decreases in nonlinear trend along with the increasing of suction. Based on Brooks Corey model and Mualem model which is shortly named as BCM model, an analytical method is put forward to calculate the permeability coefficient of compacted clay. The results of using BCM model and TRIM are compared, which show that the permeability coefficient obtained with two kinds of methods match well when the suction is greater than the inlet value.

Abstract: The reliability theory based analysis is more advanced and reasonable compared with the traditional methods for slope stability analysis. Limit equilibrium method is usually used to evaluate the stability of a slope. In this paper, a new reliability analysis method is obtained based on JC method and multi sliding surface method which a new limit equilibrium method developed by Huang. Then, this new method is applied for a wharf slope. The sliding surface get from the safety factor is not the same as that from reliability index though they are close to each other. The safety factor or reliability index get from Fellenius method is smaller than that from other method. The safety factor or reliability index get from multi sliding surface method is close to that from Bishops method. The reliability index can be more reasonable after the standard deviation of the soil property index is deduced with random field theory.