Bai G.,Design and Research Institute
Modern Tunnelling Technology | Year: 2014
Taking the Hengshanling tunnel on Dali-Lijiang expressway in Yunnan province for example, this paper analyzed the main causes and other influential factors related to floor heaving of inverted a:ch and secondary cracking of this tunnel, as well as the mechanical mechanism by lever principle based on a simplified mechanical model; put forward the basic principles and main measures for tunnel disease treatment based on above analysis; summed up the details and key points to which should be paid attention during the construction of multi-arch tunnels by considering the disease treatment process and effect. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.
Chen Y.,Design and Research Institute
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2011
Water resources allocation is to distribute the regional water resources in the watershed or within a specific region through a combination of engineering and non-engineering measures by the principles of being fair, efficient and sustainable. In this paper, a water resources allocation model is proposed with an analysis on the behaviors of water resources utilization and development in the Yangtze River basin in Jiangsu Province. This model is applied to planning of the resources in this region using the hydrological data of 1956~2000 and the forecasted water demand of the future years. © Copyright.
Wu Z.,Hunan University |
Zhang P.,Hunan University |
Zhang P.,Beijing Forestry University |
Zeng G.,Hunan University |
And 2 more authors.
Journal of Environmental Engineering (United States) | Year: 2012
Humic acid (HA) removal from water with inorganic polyaluminum coagulants is reported in this paper. Polyaluminum chloride (PAC) and three kinds of polyaluminum chloride sulfate (PACS) with a [SO42-]/[Al3+] (S) molar ratio of 0.02, 0.06, and 0.10 were prepared. The coagulation behaviors of these coagulants were investigated in the view of coagulant dosage, initial pH, and aging time. PACS (S=0.06) showed the best HA removal efficiency, and there was no restabilization within a broad effective dosage range. The proper initial pH range was broad and was 4.0-9.0 for PACS (S=0.06). The stability of PACS (S=0.06) reduced with a long aging time, so the proper aging time should not exceed 1 month. The aluminum species distribution, particle mean size, charge neutralization, and infrared spectrum of prepared coagulants were tested. Results showed that SO42-addition promoted the hydrolysis/polymerization of aluminum and reduced the charge neutralization capacity of PACS. Besides charge neutralization, the bridge-aggregation and sweep-flocculation mechanisms may play important roles for HA removal. The coexisting Ca2+ and kaolin slightly promoted the HA removal with polyaluminum coagulants. © 2012 American Society of Civil Engineers.
Lu Z.,Design and Research Institute
Proceedings of the 10th (2012) ISOPE Pacific/Asia Offshore Mechanics Symposium, PACOMS 2012 | Year: 2012
The paper presents the proposed structural solutions and the applicable conditions of the wind turbine foundation available to offshore wind farm, and the approaches to perform the analysis of typical technical issues like the foundation structure, erosion to surrounding seabed, bearing capacity of pile foundation etc and corresponding handling measures for the offshore wind farm in China. The above outcomes are concluded through study on the construction environment conditions concerning the marine hydrology, meteorology, topography and geology; and the situation of force on structure of the wind turbine foundation for offshore wind farm in China. They are worth to recommend as a reference for the construction of the wind turbine foundation of offshore wind farm in the future. © 2012 by International Society of Offshore and Polar Engineers.
Chen J.-H.,Design and Research Institute
Bridge Construction | Year: 2013
To provide reference for the planning and construction of urban viaducts, the critical factors of the structural schemes for the viaducts are summarized and the development trends of the schemes are predicted on the basis of analysis of several typical viaducts in Hangzhou City. According to the analysis, for the overall dimensions of the urban viaducts, it is proposed that the height of the viaducts should be controlled within 10-14 m. Where the geologic conditions for the foundations of the viaducts are good (poor), it will be appropriate that the span length of the viaducts should be 20-30 m (30-35 m). The height-to-span ratio of the viaducts should generally be 1:2.5-1:3 and the depth-to-span ration of the girders for the viaducts should be 1:10-1:20. For the structural types of the viaducts, the cast-in-situ concrete continuous box girders should be preferably used for the superstructures while the arc shape piers or the long cantilever column piers should be used for the substructures. The structural system for a viaduct may be the one that is simply supported first and made continuous late, the continuous system and/or the continuous and rigid-frame system. The urban viaducts will develop towards the more lightweight and aesthetic configuration, more durable structures, richer functions and also towards the direction that can better embody the environment protection conception.
Liu J.-F.,Design and Research Institute
Bridge Construction | Year: 2013
To study the working performance and actual load bearing capacity of existing presressed concrete (PC) bridges, the field static load tests for a PC continuous girder bridge in service of 20 years were made. In the tests, the load applying by stages was adopted. The test for the designed load of the bridge was carried out, the load was applied to the bridge gradually by stages until the concrete in the tensile areas cracked and the damage to the bridge appeared. The whole process of the normal operation-design load-concrete cracking of the bridge was observed and analyzed. The results of the analysis showed that the working performance of the structure of the bridge at the normal operation stage was good, however, it was found that the actual load bearing capacity of the structure decreased to some extent owing to the influences of the structural damage caused by the grouting quality of the prestressing ducts and the long-term service of the bridge.
Wang J.-J.,Chongqing Jiaotong University |
Zhang H.-P.,Chongqing Jiaotong University |
Liu T.,Design and Research Institute
Advanced Materials Research | Year: 2012
This study focuses on the method to determine the slip surface in waterfront soil slope analysis under static and seismic conditions. Based on the limiting equilibrium theory and the stress analyzing method, a new method to determine the slip surface is suggested. In the method, the two basic assumptions are considered in order to solve the problem. One is that the slip surface comprises a series of straight lines, and the other is that the interslice boundary is an inclined plane. Three balance equations for any slice are proposed. The iterative method to solve the balance equations is also suggested. In the new method, the slip surface is obtained slice by slice going from downhill to uphill in terms of the balance equations of the slice, not predefined.
Yang Y.F.,Dalian University of Technology |
Hou R.,Design and Research Institute
Thin-Walled Structures | Year: 2012
The experimental studies on the behaviour of recycled aggregate concrete-filled steel tube (RACFST) stub columns after exposed to high temperatures are reported in this paper. Forty specimens, including 32 RACFST stub columns and 8 normal concrete-filled steel tube (CFST) stub columns as reference, were tested, and the failure pattern, load versus strain relation and ultimate strength of the specimens were presented and analysed. Five types of concrete were produced: one reference concrete with natural aggregates, two concrete mixes with recycled coarse aggregate (RCA) replacement ratios of 50% and 100%, and two concrete mixes with recycled fine aggregate (RFA) replacement ratios of 50% and 100%. The specimens were exposed to 300 °C, 600 °C and 800 °C for 3 h. The test results showed that, due to the existence of the recycled aggregates, the post-fire performance of RACFST stub columns was lower than the corresponding normal CFST specimens under the same maximum temperature suffered, and the RACFST specimens with RCA had a better behaviour than those with RFA under the same recycled aggregate replacement ratio. © 2012 Elsevier Ltd. All rights reserved.
Wang P.,Design and Research Institute
Advances in Science and Technology of Water Resources | Year: 2014
Hydro Energy Design Code for Small Hydropower Projects (SL 76-2009) lacks a calculation method for hydro energy of small hydropower, mainly for irrigation, and the calculation methods commonly used in designing work are not usually reasonable. Based on analysis of the disadvantages of conventional methods, an improved calculation method, the long series calculation method, is put forward, correcting or avoiding such problems as the unreasonable assumed condition and the simplified calculation of conventional methods, etc. The results of application of the improved calculation method in practical engineering show that the improved calculation method can improve the rationality of operation of small hydropower generation and irrigation, and it can be applied in reservoirs with different regulation performance, obtaining more irrigation water and electricity production as compared with conventional methods.
Hu X.,Design and Research Institute
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2014
The principle of constructing basement nested in existing building is discussed. A indoor compensation method that compensates foundation worked expectedly under the influence of live loads on floor, and the coefficient confirmed to calculate foundation soil stress by multiplying live loads on floor are presented. Based on the proposed principle, the total loads of the underground space to be built can be balanced and compensated by the summary of no less than the following parts: one is the soil weight of foundation pit; the other is a part of the pre-consolidation pressure which mainly comes from the soil stress of floor live load. A construction case is illustrated. The research results and the engineering practice both show that the indoor compensation method was suitable to applying to constructing basement nested in existing building. As the excavation depth and the increased loads was determined according to the method, the foundation soil deformation affected by the indoor excavation and construction would no longer threaten existing building's stability and would reduce the risk of damage to the existing building.