Enhancement of a hypoplastic model for granular soil–structure interface behaviour     

H. Stutz  D. Mašín  F. Wuttke 《Acta Geotechnica》2016,11(6):1249-1261

Modelling of interfaces in geotechnical engineering is an important issue. Interfaces between structural elements (e.g., anchors, piles, tunnel linings) and soils are widely used in geotechnical engineering. The objective of this article is to propose an enhanced hypoplastic interface model that incorporates the in-plane stresses at the interface. To this aim, we develop a general approach to convert the existing hypoplastic model with a predefined limit state surface for sands into an interface model. This is achieved by adopting reduced stress and stretching vectors and redefining tensorial operations which can be used in the existing continuum model with few modifications. The enhanced interface model and the previous model are compared under constant-load, stiffness and volume conditions. The comparison is followed by a verification of two the approaches for modelling the different surface roughness. Subsequently, a validation between available experimental data from the literature versus simulations is presented. The new enhanced model gives improved predictions by the incorporation of in-plane stresses into the model formulation.  相似文献   

Soil and water conservation in mining area based on ground surface subsidence control: development of a high-water swelling material and its application in backfilling mining     

Ailong Wang  Liqiang Ma  Zhongwei Wang  Dongsheng Zhang  Ke Li  Yao Zhang  Xingjun Yi 《Environmental Earth Sciences》2016,75(9):779

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Aeolian sand transport above three desert surfaces in northern China with different characteristics (shifting sand,straw checkerboard,and gravel): field observations     

Ping Lü  Zhibao Dong  Xiaoming Ma 《Environmental Earth Sciences》2016,75(7):577

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Investigation of the adsorption/desorption equilibria of Cd(II), Zn(II) and Cu(II) ions on/from immobilized digested sludge using biosurfactants     

Urszula Filipkowska  Małgorzata Kuczajowska-Zadrożna 《Environmental Earth Sciences》2016,75(9):814

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Pressure transient analysis of multistage fracturing horizontal wells with finite fracture conductivity in shale gas reservoirs     

Yu Dai  Xinhua Ma  Ailin Jia  Dongbo He  Yunsheng Wei  Cong Xiao 《Environmental Earth Sciences》2016,75(11):940

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A fusion approach of the improved Dubois model and best canopy water retrieval models to retrieve soil moisture through all maize growth stages from Radarsat-2 and Landsat-8 data     

Qingyan Meng  Qiuxia Xie  Chunmei Wang  Jianxin Ma  Yunxiao Sun  Linlin Zhang 《Environmental Earth Sciences》2016,75(20):1377

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Analysis of phosphorus import characteristics of the upstream input rivers of Three Gorges Reservoir     

Chaonan Han  Binghui Zheng  Yanwen Qin  Yingqun Ma  Wei Cao  Chenchen Yang  Zhichao Liu 《Environmental Earth Sciences》2016,75(12):1024

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Data integration in characterizing a fracture-cavity reservoir,Tahe oilfield,Tarim basin,China     

Yongqiang Li  Jiagen Hou  Xiaoqiang Ma 《Arabian Journal of Geosciences》2016,9(8):532

Fracture-cavity reservoirs can be described in terms of storage space, filling materials and distribution, however, characterizing these variables remains a challenge. In this study, a method was developed to characterize complex reservoirs by integrating outcrop, core, well log, and seismic data from the Tahe oilfield. Outcrop analogs were used to identify and qualitatively analyze the genesis of different reservoir spaces. Cores, well logs, and seismic data were used to identify different types of reservoir space in the subsurface, to describe the spatial distribution, and to establish the distribution pattern of fracture-cavity reservoirs. Clastic sediments, collapse breccia, and chemical fillings were described from the cores and used to assess porosity and permeability. On the basis of the results, a three-dimensional geological model was constructed incorporating a structural model, a reservoir space model, and a property model. Caves and fractures were the main storage spaces and seepage passages. The cave model was built using multi-point geostatistical simulation, while the fracture model was established using deterministic modeling combined with manual interpretations and ant-tracking technology.  相似文献   

Importance of kelp-derived organic carbon to the scallop <Emphasis Type="Italic">Chlamys farreri</Emphasis> in an integrated multi-trophic aquaculture system     

许强  高菲  杨红生 《中国海洋湖沼学报》2016,34(2):322-329

Bivalves and seaweeds are important cleaners that are widely used in integrated multi-trophic aquaculture (IMTA) systems. A beneficial relationship between seaweed and bivalve in the seaweed-based IMTA system has been confirmed, but the trophic importance of seaweed-derived particulate organic materials to the co-cultured bivalve is still unclear. We evaluated the trophic importance of the kelp Saccharina japonica to the co-cultured scallop Chlamys farreri in a typical IMTA farm in Sungo Bay (Weihai, North China). The dynamics of detritus carbon in the water were monitored during the culturing period. The proportion of kelp-derived organic matter in the diet of the co-cultured scallop was assessed via the stable carbon isotope method. Results showed that the detritus carbon in the water ranged from 75.52 to 265.19 μg/L, which was 25.6% to 73.8% of total particulate organic carbon (TPOC) during the study period. The amount of detritus carbon and its proportion in the TPOC changed throughout the culture cycle of the kelp. Stable carbon isotope analysis showed that the cultured scallop obtained 14.1% to 42.8% of its tissue carbon from the kelp, and that the percentages were closely correlated with the proportion of detritus carbon in the water (F =0.993, P= 0.003). Evaluation showed that for 17 000 tons (wet weight) of annual scallop production, the kelp contributed about 139.3 tons of carbon (535.8 tons of dry mass). This confirms that cultured kelp plays a similar trophic role in IMTA systems as it does in a natural kelp bed. It is a major contributor to the detritus pool and supplies a vital food source to filter-feeding scallops in the IMTA system, especially during winter and early spring when phytoplankton are scarce.  相似文献   

From sequential to parallel growth of cities: Theory and evidence from Canada     

Kerong Sheng  Jie Fan  Wei Sun  Hailong Ma 《中国地理科学(英文版)》2016,26(3):377-388

This paper examines city growth patterns and the corresponding city size distribution evolution over long periods of time using a simple New Economic Geography(NEG) model and urban population data from Canada. The main findings are twofold. First, there is a transition from sequential to parallel growth of cities over long periods of time: city growth shows a sequential mode in the stage of rapid urbanization, i.e., the cities with the best development conditions will take the lead in growth, after which the cities with higher ranks will become the fastest-growing cities; in the late stage of urbanization, city growth converges according to Gibrat′s law, and exhibits a parallel growth pattern. Second, city size distribution is found to have persistent structural characteristics: the city system is self-organized into multiple discrete size groups; city growth shows club convergence characteristics, and the cities with similar development conditions eventually converge to a similar size. The results will not only enhance our understanding of urbanization process, but will also provide a timely and clear policy reference for promoting the healthy urbanization of developing countries.  相似文献