Advanced Materials Research Vols. 446-449

Abstract: Great achievements have been made in rock mass structure research to evaluate engineering properties of rock mass in the engineering geology field. In fact, rock mass structure can not only indicate the quantity of structural planes (discontinuities) and size of rock blocks, but also indicate the integrity and mechanical properties of the rock mass. More and more attention has been paid to rock mass quality classification by using rock mass structure. During the past 40 years, rock mass structure research has been carried out by many scholars, and various standards of rock mass structure classification have been proposed in different industries of different countries. In these standards, the most widely used index was the spacing of structural plane. However, it is a pity that the method of determining the spacing value is not unified in different standards, therefore, the structure type of a rock mass may be different according to different standard. But which kind of method to determine the spacing value is most reasonable It becomes an important problem to be solved. In this paper, rational method of determining the spacing of structural planes is demonstrated based on lots of statistical data in dam abutment rock mass of one large-scale hydroelectric project in Southwest China.

Abstract: Morphology of pyrite has been an important indicator of conditions in the ore-forming environment. This study establishes a new pyrite morphology quantification method to characterize different types of magmatic-hydrothermal gold deposits, applying this method to the Linglong, Sanshandao and Xiadian magmatic-hydrothermal gold deposits in Jiaodong peninsula, China. We used K curve and coefficient Y to characterize the Linglong type and Jiaojia type gold deposits. It showed that Linglong type and Jiaojia type gold deposits had different K curves and coefficient Y characteristics. The results showed that this method was proper in magmatic-hydrothermal gold deposits. It is concluded that the K curve and the coefficient Y are important parameters to characterize pyrite morphology in magmatic-hydrothermal gold deposits. This quantification method was called “K curve method”.

Abstract: In this article, the basic mechanical characters of recycled fine aggregate concrete (RFAC) are studied, and the relationships of recycled fine aggregate (RFA) content, minimum particle size and water content with them are also discussed according to results of cubic compressive strength （f¬¬cu）, flexural strength （ff）, splitting tensile strength（fts）, axial compressive strength（fc）and Yang’s modulus （Ec）. The results indicate that the use of RFA will induce mechanical properties of RFAC to deteriorate, and the deteriorated trend of it become more obviously with RFA content increased and minimum particle size reduced, in addition to, the early compressive strength of RFA develop slowly. The RFAC elastic modulus is significantly lower than ordinary concrete, besides, RFA on elastic modulus was significantly affected than other mechanical properties.

Abstract: Stochastic modeling technology of reservoirs has been broadly applied in clastic reservoirs while scarcely applied in carbonate reservoirs. The heterogeneity in carbonate rocks more severe than that in clastic rocks leads to more tough problems for geological modeling precisely. Taking into account of the difficulties such as extensive area to be modeled, insufficient drilling information, incomplete seismic interpretation data, lack of facies controlling constraints and sophisticated gas-water contact, a solution is proposed in this paper in which the inversed information of reservoir thickness is used as plane constraints during attribute simulation, two gas fields are constrained by different correlation coefficients and precise geological models have been set up finally through reserve calculation by use of variable gas-water contact, obtaining good results and providing a reference for this type of geological modeling.

Abstract: Through the survey and research on seismic damage phenomena of damaged towns by Wenchuan Earthquake and geological environment , this article identify that the seismic damage effect of towns damaged by Wenchuan Earthquake mainly includes four types which are fault dislocation effect、site and foundation effect、topography motion amplified action and geologic hazard effect. Site selection of the reconstruction of damaged towns and seidmic design of building and other problems are complex and systemic engineering problems, and they refer to many complex factors such as earthquake faults、geologic hazards、national well-being and the people's livelihood, economic development and so on. The basic principles of consideration should be: for the mountain towns which are located at seismic fault zone and exist serious geological disaster, they must be avoided and relocated off-site; for the towns which are away from the fault for a distance and have no fatal geological disaster risk, we should follow the principles of "scientific planning, normative avoidance and reasonablely adjust the seismic standards" and reconstruct in the former location. Reconstruction site should also pay attention to the concealment of geological hazards, the multiplicity and long-term sustainability of induced factors and so on, so we should enhance the suitability evaluation of the geological environment and risk assessment of geological disaster.

Abstract: Lithological information, rock mass fracture data and discontinuity shear strength obtained through field investigations have been used in conducting kinematic analyses for the rock slopes that exist in the Yujian River dam site to evaluate the stability of the slopes. Results given in the paper can be considered as conservative because of several conservative assumptions used in the analyses. Dam site slopes seem quite stable up to 40º dip angle. Out of the three basic failure modes, possible wedge sliding seems to be the most likely one followed up with possible plane sliding as the second. Irrespective of the considered slope regions, slope dip direction ranges 270-315º and 200-210º seem to be the worst cases for possible instability of slopes in the dam site. Regional slopes in the dam site can be ranked with respect to safety from the lowest to highest in the following order: R-c-1, R-e-2, R-c-2, R-d-1, R-b, R-a, R-d-2 and R-e-1. Note that the dam site slopes are currently stable and the existing slope angles agree well with the results obtained from the rock slope stability analyses.

Abstract: The longitudinal compression strength of single-directional fiber-reinforced composite is related to many factors, such as the mechanical properties, the fractions of components, and the distribution of flaws. There are no abroad and uniform opinions about its longitudinal compressing break mechanism yet. Thus, a review of recent developments in the compression strength mesomechanical forecasting models of single-directional fiber-reinforced composites is presented. The damage mechanisms based by these models and the affecting factors considered in them are analyzed. The application conditions of each models are shown, and the model choosing method of combining experiment and theoretical analyze is suggested.

Abstract: In this paper, we conducted some experiments as geotechnical test, standard penetration test, dynamic penetration test, loading capacity test on the dynamic compaction gravel clay foundation in Guangdong Province. We also conduct the lineal regression analysis and work out the normalized formula and the minimum-maximum equations based on PLT and other tests. We also make comparisons between the fitting equations in this paper and that in other specifications and reference items. Finally, the testing methods and empirical formulas available for the evaluation of the dynamic compaction gravel clay foundation are advanced for further surveys and designs.

Abstract: The submerged floating tunnel moored by tethers is simplified as a simply supported Euler-Bernoulli beam, and its vibration caused by vehicles passing through the tubular is also reduced as parametric excitation, moreover, the vibration governing equation of tether is still propounded by means of Galerkin method, simultaneously, the dynamic stability criterion of tether is also set up by means of Lyapunov function in this paper.

Abstract: Based on The subway station of the blast in typical pressure load model, apply ABAQUS finite element analysis software，analysis the dynamic response of the numerical simulation in the metro station under the explosion peak load. Received the subway station failure mode under the blast load，the results show that the displacements of the structure affected by the blast loading directly are several times larger than that of structure far away from the blast loading.