Applied Mechanics and Materials Vols. 170-173

Abstract: The structural property is an important influence factor in loess liquefaction, which contains the interaction between the soil granules. According to study by Gao, the loess could be divided into three types as weak cemented loess, half cemented loess and cemented loess based on the grain composition, the consolidation and the weather conditions of the loess when it formed. In this paper, based on microstructure test and dynamic triaxial test of the loess from the Loess Plateau region, liquefaction properties of structural loess was analyzed. The results show that: (1) the structural strength of loess of weak cementing type, half cementing type and cementing type increases in order, and so does the liquefaction strength, (2) the change mechanism of different structural loess’s dynamic strain during liquefying is different, (3) the change of saturation loess’s pore water pressure during liquefying is related to the type of pore and the structural strength.

Abstract: Interrill and rill erosion are commonly observed erosion processes to coexist on hillslope. Understanding of the interrill and rill erosion process is the key for the development of physically-based erosion prediction models. This paper reviewed the research progress of interrill and rill erosion, and the relationship between them. The shortages were also put forward. Finally, the trends for future development and questions are also discussed.

Abstract: In view of the broken fault, rapid sediment, high heterogeneity，high structural dip and rapid reservoir change in Block Bei301, fine reservoir description research was implemented including small fault identification, fan delta sedimentary microfacies subdivision and facies-constrained modeling, and the problems existing in production were analyzed zone by zone and interval by interval. Moreover, other unique adjustment strategies were implemented including reservoir engineering and numerical simulation researches, well pattern thickening, injection-production system adjustment, separated layer system adjustment, as well as horizontal well technology. Finally, oilfield development effect was improved and a series of unique adjustment technologies for complex fault block reservoir were preliminarily formed, which provides reference for the development adjustment in similar oilfields

Abstract: As for shallow thick coal seam, the overlying strata can not form steady structure and will break down until reach the surface ground, which will induced large ground deformation and fractures in the overlying strata during the mining. Under the condition of strong rainfall, surface runoff will influx to the collapse pit or supply to other aquifers, and inrush into the roadway through water flowing fractured zone. This paper takes the 4201、4301、4302、4303 and 4401 coal faces of JingDong mine area in PingShuo for example, predicts the range of ground subsidence、settlement and the height of water flowing fractured zone dynamically after coal face mining, with the Flac3D numerical modeling software. On the base of result above and combined with geomorphic characteristics and hydrologic geology of the mine area, the author analyses risk of surface runoff seepage and put forward a dynamic water drainage design to prevent mine water bursting, which offers scientific foundation and data for safety production of the mine .

Abstract: Taking Xi’an Bell Tower and metro line 2 as research background, at first, according to the theory of Euler-Bernoulli beam in Winkler foundation, the analysis model of train-track-foundation system was established, and then, time-history curve of metro-induced loading acts on tunnel structure is obtained by using Matlab produce platform. Secondly, two-dimensional finite element model of the structure-soil-tunnel interaction model was established using ANSYS. Taken loading time delay into consideration for the first time, dynamic response law of the bell tower under the metro-vibration loading is obtained. Finally, the impact of metro line 2 on Xi’an Bell Tower was evaluated according to the Technical specification for protection of historic buildings against man-made vibration.

Abstract: Aiming at the surrounding damage and instability in underground excavation and operation, an analysis of surrounding rock damage modes and an exploration of damage mechanism are done and an conclusion of control principles and means for surrounding rock deformation and damage is made in the thesis. The result dovetailed with engineering and provides reference for engineering design and operation.

Abstract: Based on to the theory of elasticity and structural mechanics, a reasonable cross section of a pressure tunnel was derived, and the computing formulas of the hoop and radial stress in the tunnel were given,and some suggestions were advanced for the rational design of buried tunnel.

Abstract: There existed an underground air-raid shelter group under the foundation of the proposed site, whose stability analysis and evaluation was the key problem on the safe use of the proposed site. Based on the engineering geological characteristics of the proposed site, the stability of the underground air-raid shelter under the present situation was evaluated and analyzed by the Pullman's Theory (unloading arch theory), meanwhile, the variety rule of the stress and strain of the underground air-raid shelter under the future situation was studied by the using of numerical simulation of Flac3d. Combined with the actual investigation, the results of analysis and study show that: the underground air-raid shelter is not stable under the present and future situation of the site, therefore, the relative measures must be taken.

Abstract: Code for design of road tunnel provides the calculation method of surrounding rock pressure for shallow and unsymmetrical tunnel, however, which has the applicable condition. Based on code method, the critical edge width is derived which need satisfy when using code method. Then, by assuming the retaining wall model, the analytical solution of lateral pressure for shallow and unsymmetrical tunnel under deep valley terrain is deduced. At last, taking Lijiabao tunnel belonging to Zhangzhuo highway as engineering relying and combining with the field measurement of surrounding rock pressure, the conclusion is drew by comparisons that the value from method in this paper is more close to the reality than the code method. The study results provide references with the design and construction of similar engineering and offers favorable supplement for the current code.

Abstract: Rational planning for the underground space development in subway station areas, in coordinate with the urban rail transit development, has positive impacts on the sustainable development of cities. This paper induces the space syntax method for calculating the quantitative accessibility index of the urban rail transit and detects the coordination between urban underground space use intensity and rail transit system of the 7 selected subway lines in Tokyo. The results show that the station areas with higher accessibility index are the same sort with higher underground space use intensity. This means that the space syntax method is suitable and feasible for calculation of the quantitative accessibility index of subway lines. The higher the accessibility index is, the more underground space will be needed potentially in future. The areas with high accessibility of subway lines and low intensity of public underground space develop are the key districts under potential exploitation of underground space.