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01 September 2014, Volume 31 Issue 9
    

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    RIVERLAKE SEDIMENTATION AND REGULATION
  • ZHAO Dan-lu, XING Yan, AI Cong-fang
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 1-5. https://doi.org/10.3969/j.issn.1001-5485.2014.09.001
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    A three-dimensional numerical model based on unstructured triangle grids was used for predicting the flow and time variation of bed deformation in a 180° channel bend. The standard turbulence closed model and explicit project method were employed to solve the RANS equations. The bed load transport quantity was determined with the Van Rijn formula. For a strong secondary flow and the influence of transverse bed slope on the direction of lateral bed load sediment in sharp channel bend, the simple Engelund model was employed to compute the deviation of the sediment transport. Moreover, the critical bed shear stress of incipient motion was also corrected according to the method advanced by Van Rijn. A full set of unsteady flow and bed deformation process within a same time step was predicted. The predicted bed deformation over time was compared with data from a physical model study and good agreement was found.
  • CHEN Fu-yuan, ZHOU Guang-ming, MU Jin-bin, NI Yong-qiang, XIE Dong-feng
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 6-10. https://doi.org/10.3969/j.issn.1001-5485.2014.09.002
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    Abundant tidal flat resources in Hangzhou Bay give rise to strong demand of utilization. To regularize the exploitation and make it rational and sustainable, resource zoning is carried out. Protection zone, reservation zone, control zone and exploitation zone are divided to ensure the orderly exploitation and to protect natural environment and tidal bore, and to maintain the safe operation of important infrastructures. The detailed approaches, considerations and result of tidal flat zoning in Hangzhou Bay are expounded in this paper. It could be regarded as a reference for tidal flat management and protection in other areas.
  • WATER RESOURCES AND ENVIRONMENT
  • HUAN Ying, ZHANG Wen-jing, WANG Nan
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 11-16. https://doi.org/10.3969/j.issn.1001-5485.2014.09.003
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    On the basis of relevant data and previous researches, we employ principal component analysis and select nine indicators as evaluation factors to assess the carrying capacity of agricultural water resources in the western regions of Jilin Province. Results showed that (1) the main components affecting the carrying capacity of agricultural water resources in this region include social economy, water resources utilization, cultivated land and population. As social economy, population and cultivated land area grow, the contradiction between supply and demand of water resource will be more prominent; (2) we divide the region into three levels (good, moderate, and poor) according to the degree of the carrying capacity. The north of the research area has large carrying capacity, while the south of the research area has small carrying capacity, which indicates that the contradiction between water supply and demand in the northern part of the research area is smaller than that in the southern part; (3) owing to abundant water resources, the carrying capacity in Qianguo county and urban Baicheng city are bigger than that of other regions. Meanwhile, the water-saving measures and water consumptions in these two areas are more advanced than those of other areas. To accelerate the economic growth, water utilization rate should be improved, foreign water and rainfall as well as flood should be utilized, water-saving awareness should be popularized, and proper economic measures could be implemented.
  • KANG Xiao yan, WANG Yan hui, DUAN Fu zhou
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 17-20. https://doi.org/10.3969/j.issn.1001-5485.2014.09.004
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    According to MSHDAI(Modified Shannon’s Diversity Area Index) and network distribution of surface water, an index named MSHDLI (Modified Shannon’s Diversity Length Index) was proposed to evaluate the spatial distribution diversity and scope of surface water in Shaying river catchment in central Henan Province. Furthermore, the surface water’s MSHDAI and MSHDLI and their correlation with PLAND (Percentage of landscape) and RD (River Density) with different mesh sizes were analyzed. Results reveal that there is a significant positive relationship between MSHDLI and RD (>0.9,<0.01); while the intrinsic link between MSHDAI and PLAND is more complicated. In terms of describing the diversity and scope of regional surface water’s spatial distribution, MSHDLI is of more characterization and stability than MSHDAI. They both increase as the mesh grain increasing from 100m to 5000m. The fabulous grain domain of MSHDAI is (100m, 200m); while MSHDLI is suitable for various mesh grains ranging from 100m to 5000m. Multiple waters can be described by MSHDLI. MSHDAI is powerless for the region with large reservoirs (lakes), whereas MSHDLI is applicable for various waters.
  • GAO Chao,MEI Ya-dong,LV Sun-yun,WANG Yue,YUAN Jiang-bin
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 21-28. https://doi.org/10.3969/j.issn.1001-5485.2014.09.005
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    Water resources carrying capacity (WRCC) is a basic metric for the evaluation of regional water resource security. Research on the theory and application of WRCC is of great significance. Through the factor analysis of WRCC based on DPSIR(Driving force-Pressure-State-Impact-Response) framework, we obtained a frame to primarily select indexes of four-level hierarchical structure, and constructed a comprehensive index system of WRCC. With Hanjiang River Basin as a case study, we assessed and predicted the WRCC by using the analytic hierarchy process (AHP)-fuzzy programming (Fuzzy) method. Results show that 1) in the absence of water transfer, the WRCC of the upper reaches of Danjiangkou is superior to the other two districts; 2) in the presence of water transfer, the WRCC of each district varies under the influence of inter-basin water transfer, and they can be considered as reaching a basically loadable state.
  • ENGINEERING SAFETY AND DISASTER PREVENTION
  • WANG Zhen-shuang, SHI Yu-qun, HE Jin-ping
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 29-32. https://doi.org/10.3969/j.issn.1001-5485.2014.09.006
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    In view of the shortcomings of single model used to simulate and forecast the data sequence of dam monitoring effect quantities, a new combinatorial model is constructed and an engineering example is given in this paper. In this combinatorial model, trend component, periodic component and random component of the monitoring data sequence are respectively simulated by Verhulst model,periodic extensional model and AR(p) model. The forecast methods for monitoring effect quantities can be enriched and the overall forecast accuracy can be improved with this combinatorial model, and our understanding of the variation regularity of monitoring effect quantities can also be deepened.
  • ROCKSOIL ENGINEERING
  • BAO Cheng-gang
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 33-42. https://doi.org/10.3969/j.issn.1001-5485.2014.09.007
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    The Second Stage Cofferdam is one of the most challenging structures in TGP (Three Gorges Project). Not only it is very important for TGP, but also very difficult. Some construction conditions did not appear before in cofferdam construction history. Researches were carried out during the whole process of construction of 18 years,and the construction was completed by using new theory, new technology and new materials. The cofferdam worked very well in its 4year operation. Even during its demolition, additional tests and data collection were specially arranged to explore some unclear points. Experiences of high cofferdam construction and research innovations were obtained and are applied to high cofferdam construction in west China. They will promote the water resource technology in China.
  • ZHU Sen-lin
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 43-46. https://doi.org/10.3969/j.issn.1001-5485.2014.09.008
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    To solve problems caused by large-scale deep soft soil foundation of Chaoshan Airport, the preloading method which takes plastic drainage board and sand drain as vertical drainage channels was systemically studied and was applied to the project. The preloading scheme was selected based on analysis of geological conditions of the construction site, and then the details of sand cushion laying, plastic drainage board and sand drain construction, problems and their solutions during construction were discussed. Finally the result of soil foundation treatment was verified by monitoring data. The results show that the method taken in this project is reliable, effective and suitable for the treatment of deep soft soil foundation.
  • AN Long-jin, ZHANG Hai-na,SHENG Han-wei, XIA Kai-zong
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 47-53. https://doi.org/10.3969/j.issn.1001-5485.2014.09.009
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    The stability of bedding rock slope is mainly affected by the physico-mechanical properties of slide face and the groundwater pressures on slope rock. On the basis of analysing the groundwater pressure, we established the hydrostatic pressure model of rock bedded slope in two cases (blocked outflow seam and unblocked outflow seam). Subsequently we derived the formulas for calculating slope stability coefficient and critical water height in separation fracture, and put forward the criterion for bedding-slip failure of rock slope. According to the criterion, slope will lose its stability once the water height of separation fracture or the critical rainfall intensity reaches a critical value. Calculation example verified the rationality of the proposed formulas. Results also reveal that the decrease in slope stability under the influence of groundwater is mainly related to hydrostatic pressure and uplift force instead of groundwater penetration. The results provide important guide for engineering design and construction.
  • WEI Bing-xu, HUANG Zhen, ZHOU Hai-bo, XIANG Fu-rong
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 54-58. https://doi.org/10.3969/j.issn.1001-5485.2014.09.010
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    The nonmetal acoustic detector type TH204 is used to test P-wave velocity of expansive soil under the condition of constant amplitude dry-wet circulation. The approach of using P-wave velocity to define damage variable of fatigue damage of expansive soils is proposed, and the law of fatigue damage under dry-wet circulation is explored. Results reveal that 1) with the increase of cycles, the damage variable of expansive soil increase nonlinearly under different control moisture contents, and the growth rate tends to be gentle; 2) the greater the control moisture content, the smaller the damage variable. The greater the cycle amplitude, the greater the cumulative damage variable; 3) the control moisture content plays an important role in the damage variation of the first dry-wet circulation, but from the second to the sixth cycles, the damage value variation shows no regularity with the change of control moisture content. Formula of damage evolution proposed in this research could be used to determine the damage extent of expansive soil.
  • JIANG Jing-shan, CHENG Zhan-lin, ZUO Yong-zhen, DING Hong-shun
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 59-64. https://doi.org/10.3969/j.issn.1001-5485.2014.09.011
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    The macro-mechanical properties of coarse-grained soils depend on its initial fabric and fabric variation in deformation process. Specimens of different initial fabric structures were prepared and two-dimensional parallel tests were conducted to investigate the influence of fabric on stress-strain relationship of coarse-grained soils. Particle movement was measured by computer image measure system, and fabric change in deformation process of coarse-grained soils was evaluated. Results show that (1) the stress-strain curves of parallel tests were different, which means fabric plays an important role in stress-strain relationship; (2) the orientations of branch vector and particle’s long axis enhanced with the increase of stress in the shear process before failure happened; (3) the peak deviatoric stresses increased with the increase of principal values of initial fabric; (4) the average branch length decreased slightly with the increasing of volumetric strain; (5) the average coordination number did not increase with the diminish of void ratio, which was probably related with polygon particles and big particles in small numbers.
  • GE Chun lan,ZOU Wei lie, XIA Xi lin, CHEN Cong cong, LI Zhi yong
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 65-68. https://doi.org/10.3969/j.issn.1001-5485.2014.09.012
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    Expanded polystyrene (EPS) geofoam is a novel geosynthetic material with some prominent features, including light weight, good compressibility, water resistance and heat preservation. It can be used as a lining structural layer under the concrete lining slab of underwater slope of expansive soil canal to release the expansive pressure acting on the concrete slab and to maintain matrix suction of expansive soil, thus stabilizing the canal slope. In order to further explore the mechanical characteristics of EPS under compression in this application, one dimensional compression tests and compressive creep tests on EPS of different densities (14.7 kg/m 3, 17.05 kg/m 3 , 23.4 kg/m 3) were conducted. Results show that the uniaxial stress strain relationship of EPS is significantly nonlinear and the creep strain is significant even under longterm small loading. On the basis of the test results, a constitutive model describing the whole uniaxial compression process of EPS is proposed. It is further pointed out that the influences of EPS density on its deloading property, water resistance and heat preservation properties should be taken into account when selecting EPS for lining structure of canal slope in cold region. Meanwhile, the influence of compression creep of EPS on lining structure of canal slope should also be considered.
  • KONG Ke, WANG Xiao-bo, XU Yuan-jie,PAN Jia-jun
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 69-73. https://doi.org/10.3969/j.issn.1001-5485.2014.09.013
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    Construction joint, which is resulted from underground diaphragm wall construction to deal with complex geological foundation for hydropower project, is a difficulty in engineering because it affects the overall mechanical properties of the underground diaphragm wall. According to the real geological conditions under the last part of diaphragm wall of Tongzilin hydropower project, we established finite element models of sash-shaped underground diaphragm wall with three different kinds of joints (rigid joints, hinged joints and semi-free joints). The stress and deformation of the wall respectively with these three kinds of joints were analyzed and compared under the most adverse working condition in ABAQUS non-linear simulation. The influence of joint on the stress and deformation of underground diaphragm wall was obtained. The result is a reference for similar projects.
  • WU Rui,XU Ting-ting,FANG Kun,ZHANG Teng-fei
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 74-78. https://doi.org/10.3969/j.issn.1001-5485.2014.09.014
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    According to the engineering geological and hydrogeological conditions of fault F field of a tunnel project, we analyzed the fault’s hydrogeological characteristics by determining the permeability coefficient through deep pumping, pressure test as well as recovery test. On this basis, we built a nonholonomic computation model of a horizontal underwater gallery which is in infinite water body. Furthermore, we calculated and analysed the dewatering result of four schemes (three different schemes of drainage hole layout and a well-point dewatering scheme). Finally, we compared the theoretical calculation results and concluded that the drainage hole arranged at both sides could effectively reduce the water level and meet the design requirements. Practice verified the feasibility of the dewatering scheme. It provides reference for similar tunnel projects.
  • LI Ke, JIA Zhi-gang, YU Hong-ming, SHI Hua-peng
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 79-83. https://doi.org/10.3969/j.issn.1001-5485.2014.09.015
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    Curves of water absorption process of gypsum rocks are obtained by using one-dimensional water absorbing method. Gypsum rocks from Shiziya tunnel are taken as research object. The water absorption processes are divided into two stages rapid absorption stage and constant speed stage. Water absorption is mainly concentrated in the first stage and different specimens have different absorption durations. With the increase of time, the water absorption velocity decreases and the decreasing slows down as well. Water absorption characteristic curves in 0.4 hour, 4 hours and the rapid absorption stage are all polynomial. After dry-wet cycling, the accumulated water absorption volume and average absorption velocity both increase, the absorption in early stage increases, and the rapid absorption stage is shortened. Through mercury injection experiment, it is found that the maximum diameter of gypsum rock is 2.85μm and average diameter is 0.88μm, indicating poor degree of sorting. After wetting-drying cycles, maximum diameter and average diameter increase and the sorting improves. Finally, a simple approach to obtain the range of effective pore diameter is presented using saturated absorption, capillary water absorption and mercury injection data.
  • YANG Wei-wei, ZHENG Yong-lai, DENG Shu-xin
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 84-87. https://doi.org/10.3969/j.issn.1001-5485.2014.09.016
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    A numerical model of uniaxial compression is built by FLAC3D and its validity is proved by comparing with actual test result. The elasticity modulus of element is changed while other material parameters are controlled. To research the effect of element’s elasticity modulus on rock’s uniaxial compressive strength, the elasticity modulus changes in a certain range uniformly, randomly and according to normal distribution respectively. Results show that the better elasticity modulus uniformity is, the greater rock compressive strength will be. The maximum value is equal to the result when elasticity modulus of the whole model is a same reference value. When elasticity modulus of elements changes randomly in a certain range, compressive strength becomes smaller. The greater randomness of elasticity modulus is, the smaller compressive strength will be. In the same range, rock compressive strength when elasticity modulus changes according to normal distribution is greater than that when elasticity modulus changes randomly. Both of them are smaller than the rock compressive strength when elasticity modulus value of the whole model is a same reference value. The relation can be expressed by σ1≥σEnormal distribution≥σErandom distribution≥σEuniform distribution.
  • WANG Ling-hui
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 88-92. https://doi.org/10.3969/j.issn.1001-5485.2014.09.017
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    The underground pressure hazard in the mining of thick and large ore-body by using panel insulating pillar at Dongguashan copper was analyzed by numerical simulation and microseismic monitoring. Results reveal that rock burst in the mining process is unlikely to occur with very low probability. The volume of each excavation unit should be controlled because displacement and plastic zone increase obviously due to degraded technical condition of mining using insulating pillar. As regards the simulated insulating pillar 54#, the height of excavation space should not exceed 50m, and the length should not be more than 48m. Moreover, interval mining sequence could reduce the stress concentration of engineering rock mass, and is conducive to engineering stability.
  • CHEN Zi yang, ZHAO Qi hua, PENG She qin, HAN Gang
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 93-98. https://doi.org/10.3969/j.issn.1001-5485.2014.09.018
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    The unit weight of model material in the physical simulation test on deep unloading formation mechanism of a slope is required to be equal to that of the prototype, and the strength is required to be 0.002 times that of the prototype. The model material is featured by relatively high unit weight and low strength. Developing and designing the required material is the key of the test. We conducted researches in terms of material selecting, mould designing, specimen manufacturing and mix ratio test, and finally obtained the composition, mix ratio and technique of the model material which meets the test requirements. The material is composed of iron powder, barite powder, quartz sand and rosin alcohol solution, which are mixed and compacted uniformly. The physical and mechanical parameters of the material could be adjusted in a large extent, and the content of components could also be adjusted for similar researches to get the corresponding parameters. This research is the technical assurance of the physical simulation test, and in addition, it provides experience for similar studies.
  • HYDRAULIC STRUCTURE AND MATERIAL
  • HU Shao-wei, HU Liang
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 99-104. https://doi.org/10.3969/j.issn.1001-5485.2014.09.019
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    The experimental study on mode-Ⅱ fracture of concrete is a difficult and hot issue among concrete fracture problems. Tests on 6 groups including 24 specimens about fracture propagation and mode Ⅱ fracture toughness were carried out. The parameters of failure load, concrete strain of crack tip, and crack tip sliding displacement(CTSD) were obtained through P-ε (load and strain) curve, P-t (load and time) curve and P-CTSD (load and crack tip sliding displacement) curve. The directions of crack extension was not parallel to shear force direction, but expanded from the tip of precrack to the vicinity of loading point and displayed as inclined crack. Results showed that mode Ⅱ fracture toughness varied from 0.5 MPa·m0.5 to 1.1 MPa·m0.5, and increased with the shortening of the distance from the vicinity of loading point to precrack and with the increase of initial seam height ratio. Shear fracture is prone to happen with a high and narrow shear zone.
  • HE Cheng-long, ZHOU Dan, TU Xing-huai
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 105-109. https://doi.org/10.3969/j.issn.1001-5485.2014.09.020
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    SIMP (solid isotropic microstructures with penalization) interpolation model and RAMP (rational approximation of material properties) interpolation model are employed to optimize the section of entity gravity dam. The optimization is carried out with ABAQUS as platform based on variable density method. Results suggest that by SIMP method, a large amount of cavities occur in the dam section, which requires many iterative times (mostly up to 50); whereas by RAMP model, the dam section conforms with the shape of the gravity dam and the number of iteration is small, indicating that the RAMP method is more suitable. Furthermore, the downstream of optimal model is fitted by straight line and curve, and static analysis is carried out. Results reveal that the optimized model accords with the stress and stability indexes of entity gravity dam. Curved downstream dam shape is better than straight line in practical application, because the former could ease the stress concentration zone better than straight line does.
  • INFORMATION TECHNOLOGY APPLICATION
  • ZHOU Li-feng, LIU Wen, ZHANG Zhi-zhong
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 110-114. https://doi.org/10.3969/j.issn.1001-5485.2014.09.021
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    The Informatization Planning of Yangtze River Scientific Research Institute (2013—2017) determines the construction targets and three construction tasks of informatization in the future five years. Cloud computing is acknowledged as the basis of research environment and promotes research abilities for the Institute. In this paper, the main contents of the planning are described briefly, the construction ideas of cloud computing based on visualization and resource pool are introduced, and the structure and data categories of comprehensive data center are introduced. Moreover, the technologies, methods and approaches of management informatization and scientific research informatization, as well as previous research on intelligent river basin based on cloud computing platform are expounded, the cloud framework is put forward, and the inherent relationships among intelligent river basin, internet of things (IOT) and big data are illustrated. Applications of cloud computing will improve the core competence in scientific researches.
  • HUANG Hai-feng, LI Hui-zhong, YE Sheng-sheng, WANG Shi-mei, ZHOU Huo-ming
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 115-120. https://doi.org/10.3969/j.issn.1001-5485.2014.09.022
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    Building three-dimensional geographic information system(3DGIS) for landslides has become essential for geological disaster prevention and mitigation during the construction and operation of large reservoirs. With landslides in several large reservoirs in Southwest China as research object and on the basis of 3DGIS system framework design, we present the data integration and management plan for reservoir landslides which is centered on GIS spatial database and consisted of relational database & multimedia-document base. Furthermore, we elaborate on the technical framework of 3DGIS which is based on Skyline, and describe the main functions including 3D scene browsing of reservoir region, landslides query and spatial location, browsing of landslide information, dynamic data update and management. Overall, a complete and effective data integration management platform with a fully functional three-dimension space information system is built in the 3DGIS for reservoir landslides in Southwest China. It is of practical significance for the informational management of reservoir landslides.
  • WU Yang-ming, LV Bin, SHEN Wen-zhong, YAN Yun-jie, ZHENG Yi
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 121-125. https://doi.org/10.3969/j.issn.1001-5485.2014.09.023
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    Because of the diversity and complexity of law violation cases, the process of water law enforcement and the legal documents in some local areas are not standardized. In view of this, some key technologies such as process flow and control, configurable examination and approval process, and asynchronous process control are employed for the case handling system of water administration law enforcement. In this system, functions such as case handling, case query, beforehand management, law query are available. The system promotes the standardization of water administration law enforcement, improves the efficiency of water law enforcement, unifies law enforcement workflow, regularizes punishment standard and reduces human interruption. The system was applied to 15 pilot counties of Zhejiang province, and is now under promotion throughout the whole province.
  • CONSTRUCTION AND MANAGEMENT OF WATER CONSERVANCY PROJECTS
  • JIANG Xin, LI Qi, ZHAO Jing
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 126-131. https://doi.org/10.3969/j.issn.1001-5485.2014.09.024
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    To solve the reliability issues of evaluator’s subjective estimates when evaluating programme risk, we introduced reliability analysis into programme risk estimation to improve the FAHP (Fuzzy Analytical Hierarchy Process) evaluation method. We substituted the interval estimation of evaluators with point estimation, and quantified the estimation interval given by the estimator according to the principle of set-valued statistics, thus obtaining the degree of reliability of evaluator’s subjective estimate. On this basis, we built the FAHP risk evaluation model and apply it to the evaluation of a case of road network around a hydropower reservoir. Results showed that the risk level of the programme is 0.363, which belongs to small risk.
  • PAN Fei,CHENG Sheng-guo,LIN Shan
    Journal of Changjiang River Scientific Research Institute. 2014, 31(9): 132-139. https://doi.org/10.3969/j.issn.1001-5485.2014.09.025
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    To investigate the big deformation control for soft rock tunnel construction with high geostress, we simulated the excavation of typical sections with big deformation by numerical approaches. Xiakou tunnel of Yichang-Badong Highway was taken as a case study. We adopted four construction techniques(method of ring cutting while preserving core soil, three-step method, two-sided pilot-hole method and CRD method) in the excavation simulation. By analyzing the tunnel deformation and plastic zone distribution respectively of these four techniques, we determined the stability of the surrounding rock, and analysed the advantages and shortcomings of the four methods. Results show that CRD method works best in terms of rock stability control. Finally, we verified the rationality of the construction technique by monitoring forces on the supporting structure and measuring the cumulative deformation and deformation rate. This research is an exploration on China’s soft rock tunnel construction with high geostress.