Applied Mechanics and Materials Vols. 170-173

Abstract: According to the impact on the slope characteristics, characteristics of underground ore occurrence, underground ore mining, the open pit slope can be separated by engineering geological zoning. After analyzed the factors that affect the stability of the slope rock, such as the combination relation between the slope surface and the structure surface, deposits of occurrence conditions, structural features and so on. The combination of cutting and under the action of the form may be made of the damage and determine the stability of the various partitions.

Abstract: In order to improve the electro-osmotic effect in high water ratio soil dehydration consolidation, this paper introduced an electro-osmotic installation system for extensive soil draining which were composed by special power source, electrode, vacuum pump and flow measurement device etc. Among those above, the development of special power source was the core of the system, which was mainly introduced in this paper with power electrical technology and single chip SCM technology and constitutive digital high frequency switch mode power source. The system supported a plenty of technological operations. It was available in worksite.

Abstract: Suffering the influence of the Three Gorges Reservoir impounding, Nierwan landslide already has produced very big transmutation, whose destructiveness and influence are great and wide. First, this paper introduces the characteristics of geology, structure and deformation of the landslide. On the basis of the study mentioned above, the formation mechanism and influencing factors of the landslide are deeply analyzed. Finally this paper adopts transfer coefficient method to calculate and evaluate the stability. According to study, the landslide is in the status of creeping or failure. So Nierwan Landslide needs to be controlled recently.

Abstract: In geotechnical engineering, assessment of the depth location of stratigraphic interfaces and the depth and thickness of thin layers can be critical in the design process. For example, stratigraphic interfaces can promote anisotropic soil strength response and potentially provide preferential slip planes that create slope instability. Similarly, the presence of thin, high permeability layers can alter groundwater flow regimes and rates of consolidation, which can hinder or accelerate methods of ground improvement. The piezocone penetration test (PCPT or CPTU) is an extension of the cone penetration test (CPT) and is able to measure cone tip resistance, sleeve friction and generated pore-water pressures simultaneously. The piezocone’s functionality is through the measured excess pore pressure profile, which reflects changes in the drainage conditions, and therefore soil conditions. In this paper the relationship between CPTU parameters and soil types and strata is analyzed, and the structure of a general regression neural network (GRNN) is designed, and the application program is programmed with MATLAB language. The results, identifying soil strata by CPTU, have confirmed that GRNN can be used to carry out the automatically identifying soil strata.

Abstract: In recent years, Anti-slide pile has been widely used in soil reinforcement works, but the pile soil interaction is not very clear. Numerical simulation was used in this article to analyze the soil arcing effect between anti-slide piles in non-cohesive soil and the main influencing factors, such as soil horizontal pressure, pile spacing and so on were also analyzed. The results show that there has soil arching in non-cohesive soil, and the soil arching effect becomes significantly with the horizontal earth pressure increases, but when the pressure increases to a certain degree, the soil arching will be damaged. The pile spacing is also a major factor to affect the soil arching effect, increases with the pile spacing, the soil arching effect gradually weakened.

Abstract: Miniature pore pressure transducer (PPT) Druck PDCR81 series are used widely and have been proved to have a good performance in the centrifugal tests in the past few decades. However this product has been off production due to unknown reasons from 2010. Therefore, an alternative PPT is urgently needed in the centrifuge research field. A series of comparison between a new PPT and PDCR81 series had been carried out to check its precision and responding rate at 1g and centrifugal condition. The results show that the new PPT has a nearly equivalent performance to PDCR81 series. Also some suggestions are given to modify this new PPT.

Abstract: Soil mass structure which contains structure fissures and structure bodies controls the deformation, failure and mechanical property of loess mass. Based on lots of field investigations, structure fissures of loess mass are classified and graded, types and characteristics of loess mass structures are summarized and hazard effects of fissured loess mass are discussed in this paper. It is very significant to know about the types and characteristics of structure fissures and soil mass structures for analyzing, assessing and solving engineering problems on fissured loess mass.

Abstract: Vibration effect is a major inducing factor of loess slope hazards and the basis of revealing loess slope mechanism, which often changes loess structure and decreases loess strength. Based on the GDS Lab System, the dynamic triaxial test was performed by using equivalent sine wave under strain controlling. The results are described as follows: ① there is an obvious phenomenon of stress relaxation during the cyclic loading test on Malan loess, and the degree of stress relaxation decreases with the increase of confining pressure and dynamic strain. Under the low confining pressure, Malan loess reaches certain strain only by small dynamic stress within 2% strain ranges. Under high confining pressure, Malan loess will also reach certain strain value by small dynamic stress within 1% strain ranges. At the same time, with the increase of confining pressure, the peak value of dynamic stress increases gradually. ②The dynamic failure stress of Malan loess increases linearly with the increase of confining pressure. The correlation coefficient is 0.99 and the linear regression equation is бd = 0.001б3 + 0.019. ③On the basis of Molar Coulomb failure criterion, the index of dynamic strength was c =3.36kPa, φ=16°. In comparison with the static strength, the internal friction angle decreases significantly while the cohesion slightly.

Abstract: Numerous test data accumulates in the process of gas reservoir exploration and development, so it is necessary to apply the data mining technology to this process. Influenced by the geologic factors such as structure, deposition and diagenesis, tight sandstone gas reservoir formation types are so diversified that traditional cross-plot analysis technique hardly identify the formation types. In this paper, the formation types of tight sandstone gas reservoir in Daniudi area are successfully identified using the decision tree algorithm of data mining based on hierarchical decomposition theory, facilitating the development of the gas reservoir.

Abstract: Algorithm of most optimization calculation is favor for the most technology personnel, for its result is ideal and it doesn’t need derivative of performance function. Combined with theory of nonlinear programming and optimization algorithm of reliability, calculating program is written by means of Lingo, which optimization calculation of geotechnical engineering based on reliability, and source program is grasped for the engineers. Combined example, calculating program is given, which are realized by means of Lingo, which is nonlinear programming software. By the studying, the aim is to improve calculating efficiency for most of engineers and to push forward application of structural reliability theory in geotechnical engineering.