Design of High Precision Horizontal Control Network for Large-Scale Hydropower Project

A new solution of combination network of GPS and high precise distance measurements with EDM is proposed. Meanwhile, it’s inadvisable only using GPS network without distance measurements. Three schemes: terrestrial network, GPS network and combination network are discussed for horizontal control network design of Xiangjiaba Dam in view of precision, reliability, coordinate and outlay in detail.

Financial Calculation Problems and Countermeasure Analysis of Large-Scale Engineering Construction Projects

The financial aspects of large-scale engineering construction projects profoundly influence their success.Strengthening cost control and establishing a scientific financial evaluation system can enhance the project’s economic benefits,minimize unnecessary costs,and provide decision-makers with a robust financial foundation.Additionally,implementing an effective cash flow control mechanism and conducting a comprehensive assessment of potential project risks can ensure financial stability and mitigate the risk of fund shortages.Developing a practical and feasible fundraising plan,along with stringent fund management practices,can prevent fund wastage and optimize fund utilization efficiency.These measures not only facilitate smooth project progression and improve project management efficiency but also enhance the project’s economic and social outcomes.

Modular Extremely Large-Scale Array Communication:Near-Field Modelling and Performance Analysis

This paper investigates the wireless communication with a novel architecture of antenna arrays,termed modular extremely large-scale array(XLarray),where array elements of an extremely large number/size are regularly mounted on a shared platform with both horizontally and vertically interlaced modules.Each module consists of a moderate/flexible number of array elements with the inter-element distance typically in the order of the signal wavelength,while different modules are separated by the relatively large inter-module distance for convenience of practical deployment.By accurately modelling the signal amplitudes and phases,as well as projected apertures across all modular elements,we analyse the near-field signal-to-noise ratio(SNR)performance for modular XL-array communications.Based on the non-uniform spherical wave(NUSW)modelling,the closed-form SNR expression is derived in terms of key system parameters,such as the overall modular array size,distances of adjacent modules along all dimensions,and the user's three-dimensional(3D)location.In addition,with the number of modules in different dimensions increasing infinitely,the asymptotic SNR scaling laws are revealed.Furthermore,we show that our proposed near-field modelling and performance analysis include the results for existing array architectures/modelling as special cases,e.g.,the collocated XL-array architecture,the uniform plane wave(UPW)based far-field modelling,and the modular extremely large-scale uniform linear array(XL-ULA)of onedimension.Extensive simulation results are presented to validate our findings.

Experimental investigation of creep behavior of clastic rock in Xiangjiaba Hydropower Project

There are many fracture zones crossing the dam foundation of the Xiangjiaba Hydropower Project in southwestern China. Clastic rock is the main media of the fracture zone and has poor physical and mechanical properties. In order to investigate the creep behavior of clastic rock, triaxial creep tests were conducted using a rock servo-controlling rheological testing machine. The results show that the creep behavior of clastic rock is significant at a high level of deviatoric stress, and less time-dependent deformation occurs at high confining pressure. Based on the creep test results, the relationship between axial strain and time under different confining pressures was investigated, and the relationship between axial strain rate and deviatoric stress was also discussed. The strain rate increases rapidly, and the rock sample fails eventually under high deviatoric stress. Moreover, the creep failure mechanism under different confining pressures was analyzed. The main failure mechanism of clastic rock is plastic shear, accompanied by a significant compression and ductile dilatancy. On the other band, with the determined parameters, the Burgers creep model was used to fit the creep curves. The results indicate that the Burgers model can exactly describe the creep behavior of clastic rock in the Xiangjiaba Hydropower Project.

Analysis of unlined pressure shafts and tunnels of selected Norwegian hydropower projects

Norwegian hydropower industry has more than 100 years of experiences in constructing more than4000 km-long unlined pressure shafts and tunnels with maximum static head of 1047 m（equivalent to almost 10.5 MPa） reached at unlined pressure tunnel of Nye Tyin project. Experiences gained from construction and operation of these unlined pressure shafts and tunnels were the foundation to develop design criteria and principles applied in Norway and some other countries. In addition to the confinement criteria, Norwegian state-of-the-art design principle for unlined pressure shaft and tunnel is that the minor principal stress at the location of unlined pressure shaft or tunnel should be more than the water pressure in the shaft or tunnel. This condition of the minor principal stress is prerequisite for the hydraulic jacking/splitting not to occur through joints and fractures in rock mass. Another common problem in unlined pressure shafts and tunnels is water leakage through hydraulically splitted joints or pre-existing open joints. This article reviews some of the first attempts of the use of unlined pressure shaft and tunnel concepts in Norway, highlights major failure cases and two successful cases of significance, applies Norwegian criteria to the cases and reviews and evaluates triggering factors for failure.This article further evaluates detailed engineering geology of failure cases and also assesses common geological features that could have aggravated the failure. The minor principal stress is investigated and quantified along unlined shaft and tunnel alignment of six selected project cases by using threedimensional numerical model. Furthermore, conditions of failure through pre-existing open joints by hydraulic jacking and leakage are assessed by using two-dimensional fluid flow analysis. Finally, both favorable and unfavorable ground conditions required for the applicability of Norwegian confinement criteria in locating the unlined pressure shafts and tunnels for geotectonic environment different from that of Norway are highlighted.

Sustainability Assessment and Ranking of Run of the River(RoR) Hydropower Projects Using Analytical Hierarchy Process(AHP):A Study from Western Himalayan Region of India

In the present scenario,tapping the unutilised hydropower potential is one of the highest priorities in developing countries of the world.Special emphasis is being imparted to run of the river(RoR)mode of power generation.However,the governments are now facing the dilemma whether to promote small hydropower projects(SHPs) or encourage large hydropower projects(LHPs).RoR large hydropower projects result into large scale cutting of mountains for constructing tunnels and access roads,generation of huge quantity of muck and large scale impact on flora and fauna due to diversion of rivers/streams.On the other hand,though SHPs are claimed to be greener and more sustainable by a section of researchers and energy planners but,they will be required to be set up in large number to generate equivalent amount of electricity.The aim of this study is to rank the most sustainable installed capacity range of RoR hydropower projects.To achieve this aim,the study proposes the use of quite popular multi-criteria decision making(MCDM)method of Operation Research named Analytical Hierarchy Process.A case study has been presented from Himachal Pradesh,a hydro rich state located in the western Himalayan region.As per sustainability assessment carried out in this study,hydropower projects in the capacity range 1 to 5 MW have been ranked to be the most sustainable.

Assessment of Man-made and Natural Hazards in the Surroundings of Hydropower Projects under Construction in the Beas Valley of Northwestern Himalaya

Mountain ecosystem, on the earth, has plenty of natural resources. In Himachal Pradesh all the rivers are snowfed and therefore rich in water resources. These resources have been supporting enough for the generation of electricity through introducing hydropower projects since the last decade However, every developmental activity has its own negative impacts on the surrounding environment. Due to the fragile nature of topography and delicacy of ecology of the Himalaya, it results in lot of disturbances because of high degree of human interferences like construction of major hydropower projects. The increased extent of geological hazards, such as landslides, rock fall and soil erosion, have mainly due to alike developmental interventions in the natural ecosystem. So understanding and analysing such impacts of the hydropower projects have mainly been on the environment in various forms but natural hazards have been frequent ones. The present study, therefore, focuses mainly on the Parbati Stage II （800 MW） and the Parbati Stage III （520 MW） hydropower projects; both of which fall within the Kullu district of Himachal Pradesh. Based on the perception survey of the local communities, the existing land use pattern, status of total acquired land of the residents by hydropower projects, frequent natural hazards and resultant loss to the local communities due to upcoming construction of hydropower projects surrounding to the Parbati Stage II and III have been analysed in the paper. Also, the preventive measures to mitigate these adverse impacts have been suggested to strengthen these projects in eco-friendly manner in the mountain context.

Research on Subcontractor Risk of EPC Hydropower Project in Vietnam

Engineering, procurement and construction (EPC) contracts are becoming the most popular form to undertake construction works on large-scale hydropower projects.?The EPC general contractors in Vietnam have been coped with lots of difficulties during the construction phase of hydropower projects, resulting in significant schedule delays and cost overrun. One of the reasons is poor Subcontractors capacity.?In order to overcome above, the current study attempts?to research on identification and control Subcontractors risks of delay process of EPC hydropower project in Vietnam.?Through summarizing international research achievements of previous researches relating on EPC hydropower projects combining with analysis characteristics of developing construction of EPC hydropower projects in Vietnam, the current study pointed out all kinds of subcontractor risk of delay process of EPC hydropower project in Vietnam;?a questionnaire with 18 risk elements was designed and then delivered to experts in EPC hydropower project management area. Based on the risk model, 11 main risk elements were identified which can be categorized into 3 groups.?Lastly, the current study proposed suggestions to reduce or avoid risks as well as approach to control risks.?Furthermore, the findings of this study can be a good managerial reference for project management teams who are working in other countries that have similar economic and investment environment to Vietnam to get their EPC construction project completed on schedule, thus ensuring the benefits to the government, the investor, the contractor, and the parties involved.

Research on Quality Risk of EPC Hydropower Projects in Vietnam

Engineering, procurement and construction (EPC) contracts are on the way to become the most usual form of contracting applied by the private sector to undertake construction works on large scale Hydropower projects. If EPC contract management is not implemented and controlled properly. Quality is the first important factor for any contractors who involve in the hydropower project execution. The purpose of this study is to investigate and evaluate risks causing not good quality of EPC hydropower projects in Vietnam. In addition, the study also provided the recommendations for project practitioners to mitigate the impacts of those identified risks. The findings of this study can be a good managerial reference for project management teams who are working in other countries that have similar economic and investment environments to Vietnam to get their EPC construction project completed on quality, thus will ensuring the benefits to the government, the investors, the contractors, and the parties involved.

Static and Dynamic Damage Analysis of Mass Concrete in Hydropower House of Three Gorges Project

This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of moti...

Research on Delay Risks of EPC Hydropower Construction Projects in Vietnam

In recent years, in Vietnam, economy has been developing rapidly. To ensure rapid and sustainable economic growth, strong support from the energy sector is required. Governments in Vietnam have invested in numerous hydropower projects, many of which employ the EPC (Engineering, Procurement and Construction) contract. However, the EPC general contractors are facing many difficulties, resulting in schedule delays and considerable losses. This research is conducted to highlight the main risk factors in the delays of hydropower construction projects in Vietnam. The research employs the method of statistical calculations and risk analysis to obtain feedback from experts participating in similar projects. The research outcomes are as follows: identifying the risks that can cause delays in EPC hydroelectric construction projects in Vietnam;calculating and classifying the degree of impact of each risk to the progress of the construction. The practical significance of this study is to ensure the timely completion of projects, benefits for the investors, and the EPC general contractors.

Modeling water resources under competing demands for sustainable development: A case study of Kaligandaki Gorge Hydropower Project in Nepal

The challenges posed by climate change require that the quantity and quality of water resources in Nepal be managed with sustainable development practices. The communities around the Kaligandaki Gorge Hydropower Project in the Myagdi District of Nepal depend on river flow for most of their rural and agricultural needs. Without a sustainable development plan, the growing population of the region, confined in an area with declining water resources, will face serious challenges to economic growth. Meteorological data show increasing annual average rainfall at a slight rate of about 0.284 mm/year, with erratic annual percentage change in rainfall in the area. The mean and minimum temperatures show decreasing trends at the rates of 0.05-C and 0.14-C per year, respectively. An assessment of the impacts on water availability for domestic and irrigation usage in the face of competing demands caused by the hydropower development project in the Kaligandaki Gorge was undertaken. The water demand and supply modeling were conducted using the water evaluation and planning (WEAP) model, based on discharge data from the Kaligandaki River, which were obtained from the Department of Hydrology and Meteorology, Nepal. The available data from 2001 to 2003 were used to estimate the model parameters while the stability of these parameters was tested with a validation period from 2004 to 2007. The performance of the model was assessed through statistical measures of calibration with the root mean square error and coefficient of determination, whose values were 0.046% and 0.79, respectively. Two scenarios were created in addition to the base case scenario: the discharge decrement scenario and new irrigation technology scenario. Analysis showed that a prioritization of demands will be necessary in the area in the near future for the purpose of sustainability of water resources, due to climate change impacts.

Risk and Response of China Overseas Hydropower Projects--A Vision of Corporate Social Responsibility

Recent years, with the quickening of global economic integration and the rapid development of our country, more and more Chinese enterprises begin to implement internationalization strategy and actively develop overseas business. However, the internationalized process of Chinese enterprises is not progressing smoothly. The paper systematically analyzes the risks of China overseas hydropower projects from two aspects： international environment risks and internal risks of hydropower enterprises and points out that effectively fulfilling corporate social responsibility by using Guidance on Social Responsibility （ISO26000） could help Chinese hydropower enterprises to deal with overseas risks. In order to help Chinese hydropower enterprises to improve the CSR （Corporate Social Responsibility） implementation level, the paper integrates the characteristics of hydropower enterprises with the core subjects of ISO26000, examines the key problems on the CSR work of Chinese hydropower enterprises according to requirements of ISO26000 and puts forward effective advices.

Research On Construction Traffic Safety Measures Based On FAHP Model In Hydropower Project

With the rapid expansion of hydropower projects, Construction safety problem has become one of the bottlenecks for the development of hydropower industry. Combined with the construction of the diversion channel project of Guan Yinyan hydropower station, from the point of view of construction traffic safety, based on the result of the FAHP model, factors which influence the construction safety of the diversion channel project of Guan Yinyan hydropower station have been found, relative measures focuses on the approach to eliminate hazards and guarantee construction safety have been elaborated.

Operation safety risk analysis method of hydropower project considering time-dependent effect

In order to consider the time-dependent characteristic of risk factors of hydropower project,the method of stochastic process simulating structure resistance and load effect is adopted.On the basis of analyzing the structure characteristics and mode of operation,the operation safety risk rate assessment model of hydropower project is established on the comprehensive application of the improved analytic hierarchy process,the time-dependent reliability theory and the risk rate threshold.A scheme to demonstrate the time-dependent risk rate assessment method for an example of the earth-rock dam is particularly implemented by the proposed approach.The example shows that operation safety risk rate is closely related to both the service period and design standard;considering the effect of time-dependent,the risk rate increases with time and the intersection of them reflects the technical service life of structures.It could provide scientific basis for the operation safety and risk decision of the hydropower project by predicting the trend of risk rate via this model.

Gezhouba Hydropower Project

The Gezhouba water conservancy project includes the first and largest hydropower station on the Yangtze River. The dam is 2606.5 metres long and 70 metres high with a water drop of 27 metres. Like a monster dragon lying at the outlet of the Xilin Gorge of the river, this spectacular dam blockades the east-running torrents and made them a source of money.

Stability analysis on Jinjia dam hydropower project in Chongqing City

The stability analysis is one of the chief problems at hydropower stations.The Jinjia Hydropower Station is a significant project in Southwest China.The paper adopts the rigidity limited equilibrium theory and evaluated stability of the slope body,which will provide the evidences for further detail design.

Pre-feasibility Report on Guandi Hydropower Project Passes Examination

The pre-feasibility, report and dam site selection scheme of Guandi Hydropower Project has passed examination on the Examination Meeting held in Chengdu. Sichuan Province from March 16 to March 20. 1996. It indicates a step forward toward feasibility, study and the project be put in the state development program. The programmed Guandi Hydropover