Applied Mechanics and Materials Vols. 501-504

Abstract: Determining the in-situ stress of wall rock is important for the underground cavern project. The three-dimensional (3-D) stress measurement, which is obtained by hydraulic fracturing stress measurement via measuring the stresses in boreholes with three different orientations, has been applied for the designation of cavern project. However, there are few examples that can demonstrate the reliability of 3-D stress measurement method. In this study, we showed one example of the 3-D stress results measured by hydraulic fracturing in Western China. The measured results, especially the dip angles of the maximum principle stress are consistent with those determined by focal mechanism of nearby earthquakes. This consistence indicates the reliability of the 3-D stress results by hydraulic fracturing and an expected application for regional geostress study.

Abstract: The extensive development vertical joints is one of the major features in the loess region. The joint destroyed the loess slope integrity, reduces the slope stability. First of all, through the field investigation and analysis the loess joint development characteristics, joint with slope tendency towards a big angle oblique, joints control slope trend. Secondly, according to the different regional slope stress analysis, tableland soil area is mainly by collapsibility tension, soil in the slope zone mainly by horizontal thrust produced by unloading effect, the slope area joint development is divided into collapsibility joint development zone, tension joint development zone, compression joint development zone and the excavation unloading joint development zone.

Abstract: Because of the problems, such as bad geological conditions, great difficulty of construction, and high investment cost, Fengjie new Town has changed the location three times in reservoir resettlement project. Considering the geological and regional feature, this paper first constructs the assessment index system of geological environment bearing capacity; and then obtains the weights of assessment indexes based on AHP; finally through extracting, analyzing and processing the of assessment indexes by means of GIS, gets the zone map of geological environment bearing capacity of Fengjie County Town. The results not only provide an evidence for the construction plan for Fengjie new Town, but also provide a reference for relocated cities of similar reservoir areas and city construction of hilly and mountainous areas.

Abstract: Earthquake and subsequent rainfall infiltration always easily induced slope failure. The paper takes one slope as the studying example to assess the preliminary joint effect of earthquake disturbing and subsequent rainfall on slope failure. Based on the unsaturated infiltration theory, subsequent rainfall unsaturated seepage fields of un-disturbing and seismic slope were simulated separately. The results of earthquake disturbing slope compared with the initial one were discussed in detailed. The conclusion showed seismic slope is inclined to rainfall infiltration, which obviously increased the pore water pressure and induced rise of ground water.

Abstract: The Dayaoshan, which has nearly 200 gold deposits (or mineralization points), is one of the most important gold deposits distribution areas in Guangxi, and the Gupao gold deposit is an important representative one. Previous researches have carried out numerous works there to guide the gold prospecting work. Due to multiple episodes of gold mineralization and multiple sources materials in ore-forming, there are heated debates on the era of the mine, and the main mineralization age of the Gupao gold deposit is focused on the Caledonian or Early Yanshanian. According to the distribution characteristics of the gold ore body showing in the Zhilong, Gulinao, and Dawangding gold deposit, the discussion of macro-tectonic setting of the area, as well as the comparative study of surrounding gold deposits, we conclude that the main mineralization age of the Dawangding gold deposit is Early Yanshanian, and the main mineralization may be controlled by the nearly east-west trending fold which was caused by the north-south extrusion.

Abstract: Expansive soil has the characteristics of strong swell-shrink, developing fissures and over consolidation. This kind of soil soaking into water, which leads to its volume expansion, strength reduction but compressibility decreasing make its engineering geology properties worsen. The distribution of expansive soil in Hefei is very wide, there are more pit accidents in Hefei district in recent years. Causing the accident is mainly due to the ignorance of the characteristics and damage of expansive soil. According to many years engaged in related working experience, this paper analyses two common types of damage in foundation pit accidents. Finally, throughout the analysis of several accidents, corresponding prevention measures and construction improvement scheme have been put forward.

Abstract: In China, water disaster often occurred in coal mines in recent years. According to official statistics on coal mine water accidents occurred in recent twelve years in China, major characteristics of the water disaster have been illustrated. The result shows that the number of both water accidents and corresponding fatalities decreased from 2001 to 2012. And apparently, the accidents occurred in township-owned coal mines and triggered by gob area water accounted for a higher proportion, respectively.

Abstract: In recent years, micro-pile has been widely applied to landslide treatment engineering due to its advantages in application and construction, with quite evident engineering effect. Different geological experts have focused on sundry research direction on its resistance mechanism. Based on results from numerical simulation, shearing forces of micro-pile in landslide treatment engineering with and without coupling beams were analyzed, all of which are hoped to reveal the impact of coupling beams between the top of the piles on shearing force of micro-pile group in landslide. Results from contradistinction showed that coupling beam played greater role with shearing force to segment piles, comparing with less to the force near the sliding surface. Without coupling beams, shearing force of each pile from each row suffered quite different, comparing to that of small differences with beams. With no coupling beams, first damage points were located under top of the piles at about six times the pile diameter.

Abstract: By X-ray diffraction analysis, scanning electron microscopy and other research methods, this paper detailedly analysizes types and micro-characteristics of clay minerals in the Ordos Basin, Chang 8 formation of Xifeng Oilfield. Studies suggest that clay minerals mainly include petal-like and pompon chlorite, bridge-like and curved sheet illite, page-like kaolinite. The content of illite / smectite interstratified minerals is less. Different kinds of clay minerals can lead to different kinds of reservoir damage. The chlorite mainly causes acid sensitivity. The illite and kaolinite are the main source of speed-sensitivity damage. The illite / smectite interstratified minerals could easily lead to water-sensitivity damage. Through the above studies, this paper can provide foundation of geological basis for rational development.

Abstract: With the rapid development of process of industrialization in Inner Mongolia, the environmental pollution, such as phenomenon of regional acid rain is gradually increasing. The Quaternary loess spread widely in Inner Mongolia. The ecological environment must be affected the intrusion acid rain. Meanwhile the physical-mechanical properties of original loess also are significantly influenced by the acid rain. To investigate the influence of acid rain on the physical-mechanical properties of loess, a series of triaxial tests in laboratory are carried out. The results showed that changes of PH value has significant effect on the specific gravity of soil grain, the limit moisture content , maximum dry density, and strength characteristics of loess.