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Hangzhou, China

Zhao C.,Beijing Jiaotong University | Zhang W.,Beijing City University | Gao Z.,Hanjia design group Co.
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2014

In this paper, an existing bounding-surface is modified and a state parameter based on phase transformation state is introduced. The deformation tendency of a sand at any time or any conditions can be judged correctly by state parameter. As a result, the dilatancy depends on the state in a way that yields a zero value at phase transformation state. This dependence allows a realistic modelling of the response of a sand in either loose or dense state, or in the transition from one state to another state. A comparison between model simulations and a sequence of experimental results for drained, monotonic loading conditions shows that the simulation results are consistent with the test results, which can better reflect the mechanics characteristics of sandy soil. Source


Wang X.-Z.,Zhejiang University | Wang X.-Z.,Hanjia design group Co. | Jin W.-L.,Zhejiang University | Yan Y.-D.,Zhejiang University
Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2010

For the status that corrosion of reinforcement, indetectable corrosion degree and corrosion-induced crack of existing concrete structures in chloride-laden environment, a path probability model (PPM) to predict the stochastic corrosion-crack development of reinforced concrete (RC) structures with time was proposed. The time-dependent probability distribution of steel corrosion ratio, crack width of concrete due to corrosion and percentage of corroded steel samples of elements were estimated effectively on a series of random paths of corrosion-crack process simulated by computer programme. The substructure of an RC bridge in chloride-laden environment was illustrated to verify the precise and effectiveness of the present model by the assessment result of field inspection data. The model can effectively predict the durability behavior of existing concrete structures and the predicted result is a reasonable proof for optimal strategies of maintenance and repair. Source


Zhang X.-H.,Ningbo Half Hill Investment Co. | Wu X.,Ningbo Half Hill Investment Co. | Yu J.-L.,Zhejiang University | He M.,Hanjia design group Co. | Gong X.-N.,Zhejiang University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

In soft soil foundation, the strength of soft soils is low and the quality of the construction of the conventional soil-nailing is hard to be controlled. To solve these problems, new slurry pressure type soil nailing technology is developed, and the soil-nailing ultimate resistance is calculated by carrying out the field pullout tests. In addition, the finite element software is adopted to establish the three finite element analysis model for slurry pocket pressure type soil nailing. The transfer law of load is studied, and the effects of the soil conditions and the dimensions of the grouting are analyzed. Source


Zhan T.L.T.,Zhejiang University | Xu X.B.,Zhejiang University | Chen Y.M.,Zhejiang University | Ma X.F.,Hanjia design group Co. | Lan J.W.,Zhejiang University
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2015

Landfill gas (LFG) collection efficiency is low at many municipal solid waste (MSW) landfills in China. The relevant mechanism and potential solution for this problem are studied through laboratory gas permeability tests on MSW, field LFG extraction tests at a landfill subjected to leachate drawdown, numerical assessment of the LFG collection efficiency at the landfill with different leachate levels, and engineering application of the measures to improve LFG collection. The research work outcomes are as follows: High water content in the food-rich MSW is one of the major reasons causing the high leachate level at many Chinese landfills. High leachate mounds tend to result in a high degree of saturation in waste, and hence a low gas permeability of the waste. Therefore, the LFG collection efficiency at Chinese landfills with high leachate level is lower than expected. A drawdown of leachate level at a Chinese landfill by pumping resulted in a significant increase in the LFG collection rate and the influence radius of LFG extraction wells. The dependence of LFG collection efficiency on the leachate level relative to the total waste thickness was verified and quantified. The leachate level is suggested to be controlled to less than 30% of the total waste thickness to achieve a high LFG collection efficiency. Engineering application at a Chinese landfill indicated that the retrofitted facilities, including deep vertical wells and horizontal drainage trenches, were effective in lowering high leachate level. The drawdown of leachate level resulted in an increase of LFG collection efficiency from 10-20 to 60-90%. © 2015 American Society of Civil Engineers. Source


Yan G.,Xian Jiaotong University | Feng Y.,Hanjia design group Co. | Peng L.,Xian Jiaotong University
International Journal of Refrigeration | Year: 2014

This study introduced a novel energy saving cooling system, i.e. a combined cycle coupled with a traditional vapor compression cycle with a pumped liquid two-phase cooling cycle. The system has two operation modes, i.e. the compression cycle mode driven by compressor and the pump cycle mode driven by refrigerant pump. A multi-purpose test bench was constructed to experimentally evaluate the performance of the integrated cycle system under various operation conditions. The effects of cycle working condition and the shift temperature between the two operation modes on the overall cycle performance were investigated in detail. It is found that the novel cycle system has a higher EER compared to the traditional compressor system when the ambient temperature is relatively low. The further experimental results and comparative annual energy saving analysis also indicated that the proper shift temperature is about -5 °C from the system EER and cooling capacity point of view. © 2014 Elsevier Ltd and IIR. Source

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