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He M.,University of Sichuan | Liu E.,University of Sichuan | Chen Y.,PowerChina Kunming Engineering Corporation Ltd | Tang Y.,University of Sichuan
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2017

To study the mechanical properties of structured soils under undrained conditions, the triaxial compression tests on reconstituted soils and two kinds of structured soils with initial stress-induced anisotropy and isotropy were carried out under axially loading-unloading-reloading. The soils were tested under consolidation- undrained(CU) conditions at the confining pressures of 25, 50, 100, 200 and 400 kPa, and the results of tests are analyzed with the binary-medium theory. It is found that the structured soils have stronger structures at lower consolidation stress. Meanwhile, Eave does not change significantly in different stress cycles. When the confining pressures are higher, the structures of soils are weakened, and their characteristics are similar to those of reconstituted soils. Because of the structure weakening and positive pore pressure, Eave decreases with the increase of εa. With the increase of the axial strain, the breakage rate of the bonded components and the soil particle spacing of friction components increase. In the meantime, the tendency of the volume contraction becomes more apparent when unloading. © 2017, Science Press. All right reserved.

PubMed | CAS Institute of Zoology, POWERCHINA Kunming Engineering Corporation Ltd and CAS Kunming Institute of Zoology
Type: Journal Article | Journal: Zoological research | Year: 2016

Biological invasion is a pervasive negative force of global change, especially in its effects on sensitive freshwater ecosystems. Even protected areas are usually not immune. Ptychobarbus chungtienensis is a threatened freshwater fish now almost confined to Bita Lake, in the Shangri-La region of Yunnan province, China. Its existence is threatened by the introduction of non-native weatherfishes (Misgurnus anguillicaudatus and Paramisgurnus dabryanus) by an unusual method known as prayer animal release. Periodic surveys revealed the ratio of invasive weatherfishes to P. chungtienensis has been increasing since the former species was first recorded from the lake in August, 2009. Ptychobarbus chungtienensis shows low genetic diversity in the relict Lake Bita population. Weatherfishes, however, have highly successful survival strategies. The degree of dietary overlap between the species is alarming and perhaps critical if food is found to be a limiting factor.

Zhou M.-Z.,Tsinghua University | Zhang B.-Y.,Tsinghua University | Zhang Z.-L.,Power China Kunming Engineering Corporation Ltd | Feng Y.-L.,Power China Kunming Engineering Corporation Ltd
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015

One of the key safety problems of high concrete-faced rockfill dams (CFRD) is the extrusion damage of the concrete faces. Based on analyzing several examples of high CFRD projects, the common features of extrusion damage of concrete slabs are summarized. The rotary contact-based extrusion, consisting of rotary extrusion and translational extrusion caused by the deformation of dams, is considered as the mechanism of extrusion contact between rotary slabs and the essential reason of extrusion damage of concrete slabs. Three-dimensional finite element numerical software on the basis of nonlinear contact theory is developed to solve the multi-body contact problem in CFRD. The numerical results of a submodel show that both the rotary extrusion and translational extrusion can cause severe local stress concentration on the surface of concrete slabs along the vertical joints, and that the phenomenon, which both the observed and numerical compressive strains at the middle position of the slabs are far below the ultimate value when extrusion damage occurs, can be explained reasonably by the stress concentration factor. ©, 2015, Chinese Society of Civil Engineering. All right reserved.

Tian F.,Tsinghua University | Yang P.,Tsinghua University | Hu H.,Tsinghua University | Dai C.,Power China Kunming Engineering Corporation Ltd
Water (Switzerland) | Year: 2016

Estimation of field crop evapotranspiration (ETc) and its partitioning into evaporation and transpiration, are of great importance in hydrological modeling and agricultural water management. In this study, we used a dual crop coefficient model SIMDualKc to estimate the actual crop evapotranspiration (ETc act) and the basal crop coefficients over a cotton field in Northwestern China. A two-year field experiment was implemented in the cotton field under mulched drip irrigation. The simulated ETc act is consistent with observed ETc act as derived based on the eddy covariance system in the field. Basal crop coefficients of cotton for the initial, mid-season, and end-season are 0.20, 0.90, and 0.50, respectively. The transpiration components of ETc act are 96% (77%) and 94% (74%) in 2012 and 2013 with (without) plastic mulch, respectively. The impact of plastic mulch cover on soil evaporation is significant during drip irrigation ranging from crop development stage to mid-season stage. The extent of the impact depends on the variation of soil moisture, available energy of the soil surface, and the growth of the cotton leaves. Our results show that the SIMDualKc is capable of providing accurate estimation of ETc act for cotton field under mulched drip irrigation, and could be used as a valuable tool to establish irrigation schedule for cotton fields in arid regions as Northwestern China. © 2016 by the authors.

Jia Y.,Dalian University of Technology | Chi S.,Dalian University of Technology | Xiang B.,POWERCHINA Kunming Engineering Corporation
Journal of Vibroengineering | Year: 2016

Dynamic numerical analysis by the finite element method (FEM) is widely used for the seismic performance analysis of earth-rockfill dams. The dynamic characteristics of soil, which can be measured by dynamic tests, determine the results of the FEM analysis. However, due to their high costs and long duration, dynamic tests are not feasible for many small- to middle-scale earth-rockfill dams. As a result, the analogy method is employed. Because the traditional analogy method is highly dependent on personal experience, it lacks objective and accurate orientations. In this paper, a new method to analogize the dynamic characteristics of rockfill by prototype monitoring and statistic curves is developed. To examine its effectiveness, the dynamic parameters of a middle-scale concrete-face rockfill dam (CFRD) were analogized. The results of the dynamic FEM analysis agree well with the general rules which were shown in the earthquake response and the dynamic FEM analysis response of the same type of CFRD. © JVE INTERNATIONAL LTD.

Chen X.-L.,China Earthquake Administration | Chang Z.-F.,China Earthquake Administration | Wang K.,Power China Kunming Engineering Corporation Ltd
Dizhen Dizhi | Year: 2015

Although the landslides triggered during earthquake events are common phenomena in the southwest China, the occurrence of the Hongshiyan landslide triggered by the MS6.5 Ludian earthquake in 2014 is attractive for its giant volume which exceeds ten million cubic meters. The Hongshiyan landslide formed a quake lake and inundated a village. Based on the geological and geomophological data obtained through the immediate field investigation after the earthquake, we build the Hongshiyan slope model and at the same time, we apply numerical simulation to study the landslide formation. Result indicates that the Hongshiyan slope was at safe conditions with the Factor of safety (Fs) value greater than 1, but the ground seismic motion during the Ludian earthquake lowered its Fs to a value smaller than 1, which resulted in the occurrence of the landslide. Moreover, this study shows that an existing slip surface is important for generating a giant landslide, and steep slopes without existing slip surfaces are likely to generate shallow landslides with normal volumes. ©, 2015, State Seismology Administration. All right reserved.

Pei X.J.,Chengdu University of Technology | Zhang S.,Chengdu University of Technology | Huang R.Q.,Chengdu University of Technology | Wei K.H.,Chengdu University of Technology | And 2 more authors.
Landslides and Engineered Slopes. Experience, Theory and Practice | Year: 2016

The engineered excavation in mountainous areas for land reclamation is creating numerous single-staged high embankment slopes (height 40 ∼ 50 m) on the hilly loess areas in China. With an increasing amount of failures of loess slopes to be found in major cities, embankment slopes can pose great risk to the local community and cause damages to the properties in the surrounding areas. In this article a case study disclosed a complete failure process of a high fill slope (max. height > 40 m) although it had strengthened by a combining technique of reinforced retaining walls with anchor piles. The deformation of the retaining structures ensued from the loading imposed by the construction, with cracks formed at the bottom of the pile board and retrogressed upwards. The proportion of the cracks with opening exceeding 3 mm increased with the progress of the backfill. The deformation process of the hillslope was recorded by the IBIS-L terrain deformation monitoring system at resolution of 0.1 mm. The deformation process can be divided into three phases, i.e. creep - slip - collapse, to respond to the deformation development at different stages. The instability criterion is proposed by analyzing the results of deformation characteristics of the hill slope. It indicates that the slope failure will occurs in case the slip surface be formed at s tangent angle > 75° on the deformation curve with rapid rise of acceleration from 0 mm/h2 to 8.9 mm/h2. © 2016 Associazione Geotecnica Italiana, Rome, Italy.

Li M.,Power China Kunming Engineering Corporation Ltd | Lu M.,Power China Kunming Engineering Corporation Ltd | Qian F.,Power China Kunming Engineering Corporation Ltd | Lei X.,Power China Kunming Engineering Corporation Ltd
China International Conference on Electricity Distribution, CICED | Year: 2016

For a more equitable and effective management of AGC ancillary service, the Southern Electric Power Supervision Committee promulgated two detailed regulations on the management of ancillary services and parallel running in 2009. Based on the actual data of 'Southern Power Grid '1 +5' ancillary services assessment system', this paper analyzes the Yunnan AGC auxiliary service from multiple perspectives. Based on the power supply characteristics of Yunnan grid, several improvement recommendations on AGC ancillary services are put forward. The recommendations have important roles in the improvement of regulation efficiency, the reasonable utilization of AGC capacity and the improvement of the AGC operating environment. © 2016 IEEE.

Dai H.,Shelfoil Petroleum Equipment & Services Co. | Dai H.,POWERCHINA Kunming Engineering Corporation | Li J.,Shelfoil Petroleum Equipment & Services Co.
Shiyou Huagong Gaodeng Xuexiao Xuebao/Journal of Petrochemical Universities | Year: 2015

In order to improve the monitoring efficiency and reliability of oil and gas pipeline, the monitoring method of petroleum pipeline temperature based on single-ended Brillouin optical time domain analysis has been proposed. The temperature experiment at oil and gas pipelines leakage location has been taken. The experiment results show that distributed optical fiber sensing technology based on Brillouin scattering can accurately monitor and identify the pipeline temperature change. The temperature measurement resolution can reach 3℃ and spatial resolution of 1 meter in 25 km sensing fiber. ©, 2015, Fushun Petroleum Institute. All right reserved.

Ding X.,Powerchina Kunming Engineering Co. | Zou X.,Powerchina Kunming Engineering Co.
Journal of Geomatics | Year: 2014

It is very important to ensure the stability of the slope at dam abutments for the safety of hydropower engineering during its construction. A certain hydropower station is taken as an example which is at the upstream of the Lancang River in Yunnan province. The technical project of surface deformation monitoring of its right dam abutment is introduced. Through the periodical analysis of external deformation monitoring results, the relativity analysis among the defamation, rainfall and excavation, the spatial distribution analysis of results, It has a great help to research the deformation mechanism and evaluate the stability of the slope.

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