scholarly journals Model test and numerical investigation of the effect of the impervious layer’s slope on seepage characteristics under hydraulic structures

Water SA ◽  
2019 ◽  
Vol 45 (1 January) ◽  
Author(s):  
Rasool Ghobadian ◽  
Hamed Shekari ◽  
Parisa Koochak
Keyword(s):  
Model Validation ◽  
Hydraulic Structure ◽  
Experimental Tests ◽  
Maximum Error ◽  
Hydraulic Structures ◽  
Seepage Discharge ◽  
Uplift Pressure ◽  
Uplift Force ◽  
Anisotropic Soil ◽  
Seepage Characteristics

Although the impervious layer under a hydraulic structure is rarely flat, the effect of the impervious layer’s slope, under the hydraulic structure, on seepage characteristics has not been studied to date. Therefore, this study investigated the effect of the downhill and uphill impervious layer’s slope (downhill/uphill foundation slopes) on the uplift pressure, seepage discharge and exit gradient under hydraulic structures. In order to reach this goal, a numerical model has been developed in which the general equation of fluid flow in non-uniform; anisotropic soil is solved by the finite volume method on a structured grid. The model validation was performed using the measured data from experimental tests. The results of the model validation indicated that the model calculates the seepage discharge and uplift pressure with a maximum error of less than 3.79% and 3.25%, respectively. The results also indicated that by increasing the downhill foundation slope (DFS) the uplift force decreases, but the exit gradient and seepage discharge increase. Moreover, by increasing the uphill foundation slope (UFS), the uplift force increases but the exit gradient and seepage discharge decrease. In addition, the results demonstrate that by increasing the length of the cut-off wall the effect of the DFS on decreasing and UFS on increasing the uplift pressure force becomes more severe. However, the effect of the DFS on increasing the seepage discharge and UFS on decreasing the seepage discharge becomes milder as the length of the cut-off wall increases. By increasing the DFS, from zero to −15%, the exit gradient increases 19.75% and 14.4% for 1 m and 6 m cut-off lengths, respectively.

The Effect of Cutoffs on the Uplift Pressure Beneath the Hydraulic Structures Floor

2018 ◽  
Vol 6 (3) ◽  
pp. 20-28
Author(s):  
Faisal Al Tabatabaie ◽  
Dhabia Sabeeh Al Waily
Keyword(s):  
Potential Energy ◽  
Hydraulic Structure ◽  
Hydraulic Structures ◽  
Outer Face ◽  
Analogue Model ◽  
Electrical Analogue ◽  
Uplift Pressure ◽  
Different Depths ◽  
The Stability ◽  
Critical Sections

The use of cutoffs underneath the hydraulic structures is considered a safe solution to ensure the stability of hydraulic structure against uplift pressure and piping phenomenon in addition to the sliding and overturning forces of the water. These cutoffs are used at critical sections underneath the floor of hydraulic structure to substitute with their depths the horizontal lengths of the creep line of the hydraulic structure base. In this paper, the experimental method- by using electrical analogue model- was carried out to plot the flow net and study the efficiency of the front and rear faces of the cutoffs for dissipating the potential energy of the percolating water underneath the floor of hydraulic structure. An electrical analogue model which was used in this study consists of twenty five models with different depths of upstream and downstream cutoffs. After plotting the flow net for all models, it is concluded that the efficiency of the inner sides are less than that of the outer sides which were investigated before in this topic of this work that both faces reduction values in the uplift pressure are considered the same, where the efficiency of the outer face of upstream cutoff is (70.35) % and for the inner face is (29.64)%, while for the downstream cutoff the efficiency for the outer face is (76.21)% and for the inner face is (23.79)% .

scholarly journals Influence of Cavity Under Hydraulic Structures on Seepage Characteristics

2018 ◽  
Vol 7 (4.20) ◽  
pp. 461 ◽  
Author(s):  
Asmaa Abdul Jabbar Jamel ◽  
Muataz Ibrahim Ali
Keyword(s):  
Coefficient Of Determination ◽  
Hydraulic Structures ◽  
Structure Model ◽  
Sheet Pile ◽  
Uplift Pressure ◽  
Coefficient Of Permeability ◽  
Seepage Characteristics ◽  
The Stability ◽  
Seepage Properties ◽  
Different Characteristics

Cavities under hydraulic structures have a significant influence on the stability of these structures. This study depends on (SEEP/W) software for a hydraulic structure model with an upstream sheet pile. Thus, different results are obtaining for discharge, uplift pressure and exit gradient. For the output a dimensional analysis is perform to study the effect of these variables. Also (SPSS), where special equations are obtaining for seepage discharge, uplift pressure and exit gradient has a coefficient of determination and correlation (0.9, 0.89, 0.8) respectively. The effect of the presence of the cavities on seepage properties whenever the location of the cavity before the sheet pile increased its effect on the discharge and uplift pressure in contrast to the exit gradient where cavity approaching the end of the structure that is increasing its impact on the exit gradient. Also decrease the depth of the cavity from ground increase its impact on the characteristics of seepage, as well as the greater coefficient of permeability and the diameter of the cavitation will increase seepage properties. Also shows that when comparing the state of the presence of cavity with the absence of it, different behaviors with different characteristics of seepage will appear at different percentage.

METHODS OF FORECAST CALCULATION OF GROUND WATER BACKWATER IN THE ZONE OF HYDRAULIC STRUCTURES INFLUENCE

2020 ◽  
pp. 109-116
Author(s):  
N.P. KARPENKO ◽  
◽  
M.A. SHIRYAEVA
Keyword(s):  
Numerical Model ◽  
Computer Program ◽  
Ground Water ◽  
Programming Language ◽  
Hydraulic Structure ◽  
Hydraulic Structures ◽  
Software Model ◽  
Computational Program ◽  
Specific Object ◽  
Zone Of Influence

The purpose of the work is to consider methods for calculating the forecast of groundwater backwater in the zone of influence of hydraulic structures. The analysis of analytical dependences of calculation of the forecast of groundwater backwater for various calculation schemes is carried out. For a homogeneous scheme of the geofiltration structure, a numerical model is proposed and a computational program for calculating the groundwater backwater is developed. It allows calculating the groundwater backwater from the channel at any time in the discrete mode. To simplify the solution of the problem of calculating the groundwater backwater, a computer program was created in the programming language Phyton Version 8.3 which quickly solves this hydrogeological problem. A possible range of geofiltration parameters is proposed for calculating the groundwater backwater near main channels. The adaptation and implementation of the software model was carried out for a specific object – the Bolshoy Stavropol channel-5, for which forecast calculations were made. The results of predictive calculations of groundwater backwater are the basis for the assessment of areas of possible flooding – the territory within which the level of ground water increases as a result of their backup by a hydraulic structure.

MPACT OF SHOCK WAVES IN INERT MEDIA ON THE OPERATIONAL RELIABILITY OF LOW-PRESSURE EARTH DAMS

2021 ◽  
pp. 52-57
Author(s):  
E. V. ANDREEV ◽  
Keyword(s):  
Gas Dynamics ◽  
Degrees Of Freedom ◽  
Room Temperature ◽  
Hydraulic Structure ◽  
Operational Reliability ◽  
The Body ◽  
Hydraulic Structures ◽  
Safety And Reliability ◽  
Gas Molecules ◽  
Internal Degrees Of Freedom

During the operation of pressure hydraulic structures, there is an objective need to ensure their safety and reliability. In the case of non-stationary loads on hydraulic structures, they can be either seriously damaged or destroyed. One of the non-stationary effects can be considered a directed explosion on the body of a hydraulic structure or in the immediate vicinity of it. At significant Mach numbers, the processes of excitation of the internal degrees of freedom of molecules, ionization and dissociation of gas molecules, and their recombination occur behind the shock wave front. The course of these processes is due to the almost tenfold compression of the gas at the time of the explosion and it’s heating relative to the room temperature of the order of 104 K. The use of approximate and numerical methods is a consequence of the difficulties associated with the need to solve nonlinear equations of gas dynamics, with the simultaneous use of relaxation equations and equations of chemical kinetics at the same time.

Hydraulic Structure Design Concept and Practice - Tacheng Reservoir Project in Xinjiang as an Example

2012 ◽  
Vol 212-213 ◽  
pp. 805-809
Author(s):  
Xiang Hong Huo ◽  
Ying Jie Chen ◽  
Jun Jing Mu ◽  
Shao Jie Li ◽  
Jian Liu ◽  
...  
Keyword(s):  
Hydraulic Structure ◽  
Building Design ◽  
Structure Design ◽  
Hydraulic Structures ◽  
Material Function ◽  
Design Elements ◽  
Mental Functions ◽  
Water Project ◽  
Project Construction ◽  
Reservoir Project

The hydraulic structure visual forms are both a water project construction component, but also the important contents in the design of hydraulic structures. So that at the same time to satisfy the engineering function, given a certain culture connotation and time spirit, become the material function and mental functions complement each other forms. The article integrates design elements according to parts of Xinjiang reservoir project building design, , puts forward the according design thought and method.

scholarly journals The Effects of Grout Curtain Parameters on Uplift and Piping Phenomenon; Case Study: Sattarkhan Dam

Hydrology ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 71
Author(s):  
Kambiz Meshkabadi ◽  
Yousef Zandi
Keyword(s):  
Numerical Models ◽  
Grout Curtain ◽  
Hydraulic Structures ◽  
Uplift Pressure ◽  
The Core ◽  
Horizontal Drainage ◽  
Potential Risks ◽  
Dam Core ◽  
Water Seal

Design of earth dams and their issues during and after construction is very important for residents downstream of the dam because of the potential risks and possible breakdowns. In the design of dams, various forces influence the dam body, including uplift pressure and piping phenomenon which should be considered in order to ensure the safety of the dam. Among the measures taken to prevent the washing away phenomenon, the reduction of the output gradient, and the leakage discharge from beneath the hydraulic structures, construction of the grout curtain and installation of the drainage are applicable. Therefore, in order to investigate the effect of various parameters such as the gradient angle of the grout curtain, length, and distance and the number of grout curtains, as well as the length of the drainage on the pressure and output gradient of the numerical models, were considered in current study. For this purpose, the SEEP/W software was used for modeling on Sattarkhan Dam as a case study. The results of the analysis showed that the use of the Qa’im grout curtain at the upstream of the dam has the highest resistance against the pressure and piping phenomenon. The results also showed that increase in the length of the curtain of the water seal increases safety against uplift and piping phenomenon. The use of further spacing between the two grout curtains under the core of the dam led to increase in overall pressure or reduction in safety against uplift pressure. Increase in the length of the horizontal drainage reduced the effects of uplift pressure and output gradient. Results show that period of 70 to 110 degree is appropriate for curtain angle and setting curtain in upstream of dam core with angle of 70 to 80 degree is optimum and economic. A length of 30 m is optimum for curtain. The number of 2 curtains is also optimum. Studying various scenarios of distance of 2 curtains in dam core indicates that distance of 6 m is optimum and also length of 18 m for horizontal drainage is optimum.

Seismic analysis of hydraulic structures affected by alkali-aggregate reaction: a case study

2001 ◽  
Vol 28 (2) ◽  
pp. 332-338 ◽  
Author(s):  
M Parvini ◽  
S Pietruszczak ◽  
V Gocevski
Keyword(s):  
Power Plant ◽  
Single Unit ◽  
Hydraulic Structure ◽  
Seismic Analysis ◽  
Numerical Procedure ◽  
Seismic Excitation ◽  
Hydraulic Structures ◽  
Seismic Load ◽  
Alkali Aggregate Reaction

This paper describes the results of numerical analysis of a hydraulic structure subjected to seismic load. The paper is divided into two main parts. First, a numerical procedure for the description of mechanical effects of alkali-aggregate reaction in concrete structures is briefly outlined. Subsequently, a single unit of the Beauharnois power plant, situated in Quebec (Canada), is analysed in the context of seismic excitation. The numerical simulations are aimed at assessing the dynamic stability of this unit and investigating the evolution of damage associated with inception of macrocracks.Key words: alkali-aggregate reaction, plasticity, seismic analysis, hydraulic structures.

scholarly journals Construction, operation, and maintenance of rubber dams

2002 ◽  
Vol 29 (3) ◽  
pp. 409-420 ◽  
Author(s):  
X Q Zhang ◽  
P W.M Tam ◽  
W Zheng
Keyword(s):  
Flood Control ◽  
Management Practices ◽  
Hydraulic Structure ◽  
Hydraulic Structures ◽  
Maintenance And Repair ◽  
Rubber Dam ◽  
The Past ◽  
Operation And Maintenance ◽  
Construction Operation ◽  
Rubber Dams

Rubber dams are inflatable and deflatable hydraulic structures. Thousands of rubber dams have been installed worldwide for various purposes: irrigation, water supply, power generation, tidal barrier, flood control, environmental improvement, and recreation. Furthermore, rubber dams have been used in cold areas where the temperature is as low as – 40°C. The simplicity and flexibility of the rubber dam structure and its proven reliability are key considerations in its wide scope of applications. Based on the management practices of 20 rubber dams in Hong Kong in the past 35 years, interviews with rubber dam experts and practitioners, and the investigation to the construction of a recent rubber dam, this paper provides a detailed discussion on various issues related to the construction, operation, maintenance, and repair of rubber dams.Key words: construction, hydraulic structure, maintenance, operation, repair, rubber dam.

scholarly journals Experimental and Numerical Analysis of Flow Behavior for Reverse Circulation Drill Bit with Inserted Swirl Vanes

Geofluids ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Cheng Yang ◽  
Jianliang Jiang ◽  
Bo Qi ◽  
Guoqing Cui ◽  
Liyong Zhang ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Structural Parameters ◽  
Flow Behavior ◽  
Experimental Tests ◽  
Maximum Error ◽  
Influential Factors ◽  
Drill Bit ◽  
Entrainment Ratio ◽  
Helical Angle ◽  
Reverse Circulation

A swirling drill bit designed with an integrated vane swirler was developed to improve reverse circulation in down-the-hole hammer drilling. Its entrainment effect and influential factors were investigated by CFD simulation and experimental tests. The numerical results exhibit reasonable agreement with the experimental data, with a maximum error of 13.68%. In addition, the structural parameters of the swirler were shown to have an important effect on the reverse circulation performance of the drill bit, including the helical angle and number of spiral blades, swirler outlet area, and the flushing nozzles. The optimal parameters for the swirling drill bit without flushing nozzles include a helical angle of 60°, four spiral blades, and the area ratio of 2, while it is about 30°, 3, and 3 for the drill bit with flushing nozzles. Moreover, the entrainment ratio of the drill bit without flushing nozzles can be improved by nearly two times compared with one with flushing nozzles under the same conditions.

scholarly journals Load and resistance factors for earth retaining, reinforced concrete hydraulic structures based on a reliability index (β) derived from the Probability of Unsatisfactory Performance (PUP) : phase 2 study

2021 ◽  
Author(s):  
Robert Ebeling ◽  
Barry White
Keyword(s):  
Reinforced Concrete ◽  
Hydraulic Structure ◽  
Limit State ◽  
Hydraulic Structures ◽  
Army Corps ◽  
Second Phase ◽  
Limit States ◽  
Two Phase ◽  
Topic Area ◽  
Load And Resistance Factor

This technical report documents the second of a two-phase research and development (R&D) study in support of the development of a combined Load and Resistance Factor Design (LRFD) methodology that accommodates geotechnical as well as structural design limit states for design of the U.S. Army Corps of Engineers (USACE) reinforced concrete, hydraulic navigation structures. To this end, this R&D effort extends reliability procedures that have been developed for other non-USACE structural systems to encompass USACE hydraulic structures. Many of these reinforced concrete, hydraulic structures are founded on and/or retain earth or are buttressed by an earthen feature. Consequently, the design of many of these hydraulic structures involves significant soil structure interaction. Development of the required reliability and corresponding LRFD procedures has been lagging in the geotechnical topic area as compared to those for structural limit state considerations and have therefore been the focus of this second-phase R&D effort. Design of an example T-Wall hydraulic structure involves consideration of five geotechnical and structural limit states. New numerical procedures have been developed for precise multiple limit state reliability calculations and for complete LRFD analysis of this example T-Wall reinforced concrete, hydraulic structure.

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