Groundwater Seepage Field Research Articles

Numerical Simulation and Analysis of the Influencing Factors of Foundation Pit Dewatering under a Coupled Radial Well and Curtain

It is crucial to use a suitable dewatering technique to prevent land subsidence and substantial decreases in groundwater levels caused by the dewatering of groundwater during the construction of underground projects. Therefore, in this study, a generalized three-dimensional numerical model of groundwater flow was implemented for an underground station pit project. The dewatering efficiency of the coupled radial well-curtain method was investigated and compared with that of a traditional method. In addition, the influence of different structures and parameters (radial pipe diameter, conductance, number of radial pipes, and shaft drawdown) on the dewatering efficiency was assessed. The results showed the following: (1) radial wells caused less disturbance to the groundwater seepage field and extracted less groundwater during the dewatering process compared with pumping wells; (2) the structure and parameters of the radial wells positively correlated with the dewatering efficiency; (3) the curtain improved the dewatering efficiency, resulting in lower amounts of groundwater discharged and less disturbance to the groundwater flow field; and (4) the coupled radial well-curtain method is an efficient dewatering method that could effectively prevent the lowering of groundwater level outside the foundation pit, thus reducing the risk of land subsidence in the surrounding area.

Study of the impact of reservoir water level decline on the stability treated landslide on reservoir bank

Affected by the reservoir water and rainfall and other factors, the stability of the landslide changes with the different reservoir water level decline rate. Using the Baota landslide in Yunyang County in Three Gorges Reservoir region as an example, and applying the saturated-unsaturated numerical simulation method, the groundwater seepage field is calculated when the reservoir water level rises and declines. The calculated pore water pressure is used for the ultimate equilibrium analysis of landslide, and the effect of reservoir water level drop on landslide stability was discussed. The calculation results show that with the water level falling from 159 m to 145 m, and the increase of the rate of decline in the reservoir water level, the decline in groundwater seepage lines has increased somewhat. The landslide stability coefficient calculated under each working condition is larger than that in the original design, and the decrease rate of reservoir water has a qualitative effect on the stability of the landslide, but the influence is very small. Through the SBAS-InSAR time series monitoring of Sentinel-1 data in the 13th period and field verification, it is found that the cumulative deformation of the slope is small, which prove the stability of the landslide.

Characterization of Shallow Groundwater Circulation Based on Chemical Kinetics: A Case Study of Xiong’an New Area, China

Xiong’an New Area, located in the middle of the North China Plain, will have been built as a “city of the future.” Urban planning and construction need to comprehensively consider the constraints of hydrogeological conditions such as aquifer structure and parameters. As the main aquifer in this area, the paleo-channel is heterogeneous and anisotropic, and the two-dimensional hydraulic conductivity in each horizontal direction cannot be obtained from aquifer tests. Therefore, this study adopts a chemical kinetics method to calculate the ionic activity and mineral saturation indices of shallow groundwater, determine the groundwater chemical potential field, and construct a horizontal two-dimensional groundwater chemical kinetics model. This model is used to calculate the hydraulic conductivity, flow rate and retention time of groundwater in areas of different chemical kinetics, as well as evaluate horizontal heterogeneity of the Quaternary paleo-channel aquifer. The results indicate that the groundwater chemical potential field can reflect the characteristics of the groundwater seepage field in each horizontal direction. The paleo-channel is the main channel of groundwater circulation, which shows the statistical difference of its permeability. Alluvial and lacustrine strata affect groundwater circulation due to their different hydrogeological structures and permeability. The groundwater chemical kinetics results of hydraulic conductivity along the paleo-channel are approximately consistent with traditional hydrogeological calculation results derived from aquifer test data. Hydraulic conductivity is higher in the extension direction of the paleo-channel, and lower if the path crosscuts multiple paleo-channels. This feature can be used to build a hydrogeological structure model combined with drilling data. Furthermore, excessive groundwater exploitation will change the actual flow rate and retention time of groundwater, thereby affecting the groundwater circulation conditions. This study of groundwater circulation in Xiong’an New Area by means of chemical kinetics makes up for the deficiency in the study of the unconsolidated sedimentary aquifer anisotropy within the paleo-channel.

Influence of Groundwater Heat Pump system operation on geological environment by Hydro-Thermal–Mechanical–Chemical numerical model

Groundwater Heat Pump (GWHP) systems have gained attention for space heating and cooling due to its efficiency and low installation costs. It is known that thermal transfixion and land subsidence are main geological environmental hazards in the application of GWHP. But few studies paid attention to groundwater quality. In this research, a three-dimensional Hydro-Thermal–Mechanical–Chemical numerical model was established based on Biot’s consolidation theory, solute and heat transport in porous media theory. The numerical model could evaluate geological environment from four aspects: hydraulic head, temperature, groundwater quality, and land subsidence. The coupling effect of building load and extraction–injection groundwater is considered to study land subsidence. The model is applied to a GWHP in Nantong, China. The results show that increasing the temperature change and decreasing the circulation ratio of GWHP will alleviate thermal accumulation, thermal transfixion, and freshwater salinization of the confined aquifer III. But it will aggravate the occurrence of land subsidence. The geological environment involves four factors. The development of shallow geothermal energy should be considered comprehensively. Optimizing operation scheme by changing the groundwater seepage field would alleviate geological environment deterioration.

Research on Seepage Control of Jurong Pumped Storage Hydroelectric Power Station

Based on the geological and hydrogeological conditions of the Jurong Pumped Storage Hydroelectric Power Station (JPSHP), a 3D groundwater flow model was developed in the power station area, which took into account the heterogeneity and anisotropy of fractured rocks. A control inversion method for fractured rock structural planes was proposed, where larger-scale fractures were used as water-conducting media and the relatively intact rock matrix was used as water-storage media. A statistical method was used to obtain the geometric parameter values of the structural planes, so as to obtain the hydraulic conductivity tensor of the fractured rocks. Combining the impermeable drainage systems of the upper storage reservoir, underground powerhouse and lower storage reservoir, the 3D groundwater seepage field in the study area was predicted using the calibrated model. The leakage amounts of the upper storage reservoir, powerhouse and lower storage reservoir were 710.48 m3/d, 969.95 m3/d and 1657.55 m3/d, respectively. The leakage changes of the upper storage reservoir, powerhouse and lower storage reservoir were discussed under the partial and full failure of the anti-seepage system. The research results provide a scientific basis for the seepage control of the power station, and it is recommended to strengthen the seepage control of the upper and lower storage reservoirs and the underground powerhouse to avoid excessive leakage and affect the efficiency of the reservoir operation.

Normalization processing and research of multi-field data in reservoir seepage investigation

Field analysis is one of the important methods to investigate the leakage of reservoir. Groundwater seepage field, groundwater temperature field, groundwater chemical field (conductivity field) and isotope field are widely used in leakage of reservoir. In this paper, the indexes of a single field are normalized according to some factors, including the relationship between field indexes and leakage sources, the relationship between field indexes and natural field background values of geological media, the variation of indexes in adjacent space, and the changes of indexes at different times. After processing, the characteristic values of the single field are obtained, including the tracer index characteristic value, the background index characteristic value, the gradient index characteristic value and the time series index characteristic value. Based on the reliability of the data and the correlation with the leakage, different weighting factors can be selected for each characteristic value to obtain a normalized field comprehensive index characteristic value. The indexes of different fields can also be superimposed according to the normalized characteristic value to realize the comparison and verification of each field. It makes full use of the limited data thus to reducing the interference information and amplifying the leakage signal. And it makes the field analysis method of groundwater leakage quantitative and systematic, which can effectively process the field data and more significantly delineate the possible groundwater leakage location.

Stability Analysis of Surrounding Rock of Large Semi-underground Pump House under Complex Conditions

The stability of the surrounding rock of large underground water-diversion projects is a critical safety concern. The water intake pumping station of a water-transfer project in Guizhou Province adopts the form of semi-underground pump house. The plane size of the main pump house is 93.5 × 40.0 m, and the maximum excavation depth is nearly 85 m, making it a large underground cavern. The project site is in a karst area with a complex geological environment, and multiple faults cross the main pump house. As a result, the groundwater seepage field affects the stability of the surrounding rock after the reservoir is impounded. We used the connotative composite element method to simulate faults, and numerical simulations to analyze the stability of the surrounding rock during multi-stage excavations. The results demonstrate that the effects of the faults and seepage are significant, the influence of complex geologic faults on the stability of surrounding rock is reflected effectively by using the connotative fault element method, and using shotcrete bolt support and optimizing construction can make caverns under complex conditions safer.

Determination method of water gushing runoff zones in the open pit mining area

Taking the Hejing limestone mining area of Guangxi Huarun Cement (Pingnan) Company as the research background, the method for water gushing runoff zones of open pit mining area is determined based on numerical simulation and field test. First of all, the calculation model of groundwater movement in open pit mining area is established by the equivalent continuous medium model. Then, calculation parameters of the model are reasonably valued through analyzing the development of karst degree, tracer tests, and pumping tests in drilling holes. Secondly, three existence forms of groundwater seepage field are put forward, and the distribution of groundwater runoff zones is determined by using numerical simulation to analyze the groundwater seepage field influence rules of water accumulation points (such as private mining pit). Thirdly, the results are verified by field tests. The water source and ground water connection in open pit mining area are determined. The results show that (1) the water gushing in the mining area mainly comes from the east and the south. The groundwater flow in the east is uniform, and the most of groundwater is fissure water gushing. (2) The groundwater flow in the south of the mining area is banded, and the most of groundwater is pipe gushing. The results of this research provide a theoretical basis for locating the groundwater runoff zones in karst open pit mining areas.

Hydrogeochemical evolution of multilayer aquifers in a massive coalfield

Groundwater is an important drinking water resource worldwide. However, mining could influence the natural groundwater geochemistry, reducing the correct discrimination of inrush sources and affecting mine safety. To accurately identify potential inrush sources in the future, hydrogeochemical processes and their evolution should be investigated using multiple analytical methods. In the study, based on hydrochemical analysis and multivariate statistical methods, the major ion chemistry of groundwater in multi-aquifer groundwater systems was analyzed in the Huainan coalfield (Anhui Province, China). The results showed that the hydrogeochemical processes in this area consisted of the three subprocesses: dissolution, desulfidation, and cation exchange. For the Cenozoic bottom aquifer and the Ordovician aquifer, the major hydrogeochemical processes are the dissolution of salt rock, silicate, carbonate, and sulfate, followed by cation exchange; for the Permian and Carboniferous aquifers, the main hydrogeochemical processes are desulfidation and cation exchange, followed by dissolution. From the Permian aquifer to the Carboniferous aquifer and then to the Ordovician aquifer, the concentration of SO42− increased, while the concentration of HCO3− decreased due to enhanced sulfate dissolution and weakened desulfurization. However, long-term mining activities changed the groundwater seepage field and the hydrogeochemical field, causing hydrogeochemical evolutionary processes with obvious zoning. The eastern discharge zone showed the strongest dissolution and the weakest desulfidation and cation exchange; from the eastern discharge zone to the central runoff zone, dissolution weakened, while desulfidation and cation exchange were enhanced; and in the western recharge zone, desulfidation and cation exchange were the strongest, while dissolution was the weakest.

Groundwater flow simulation and its application in GaoSong ore field, China

Abstract Mine water inrush is one of the important factors threatening safe production in mines. The accurate understanding of the mine groundwater flow field can effectively reduce the hazards of mine water inrush. Numerical simulation is an important method to study the groundwater flow field. This paper numerically simulates the groundwater seepage field in the GaoSong ore field. In order to ensure the accuracy of the numerical model, the research team completed 3,724 field fissure measurements in the study area. The fracture measurement results were analyzed using the GEOFRAC method and the whole-area fracture network data were generated. On this basis, the rock mass permeability coefficient tensor of the aquifer in the study area was calculated. The tensor calculation results are used in the numerical model of groundwater flow. After calculation, the obtained numerical model can better represent the groundwater seepage field in the study area. In addition, we designed three different numerical models for calculation, mainly to explore the influence of the tensor assignment of permeability coefficient on the calculation results of water yield of the mine. The results showed that irrational fathom tensor assignment would cause a significant deviation in calculation results.

A groundwater seal evaluation method based on water inflow for underground oil storage caverns

A novel groundwater seal evaluation method based on water inflow for is proposed. The groundwater seepage field and the water inflow of an oil storage cavern obtained with different water curtain parameters are studied via numerical simulations. The sensitivity of water inflow to various water curtain hole parameters is studied based on regression analysis. A novel concept of minimum water inflow is proposed, and the weak area of the groundwater seal is revealed. The results indicate that the water curtain pressure (p), the length of the water curtain hole (l), and the inclination angle (a) are positively correlated with water inflow, while the water curtain hole spacing (s) is negatively correlated with water inflow. The relative influences of water curtain system parameters on the groundwater seal of the oil storage cavern are ranked as follows: p > l > s > a.

Analysis of the influence of the interlayer staggered zone in the basalt of Jinsha River Basin on the main buildings

In this paper, the finite element software FEFLOW is used to simulate the seepage field of the interlayer staggered zone C2 in the basalt of Jinsha River Basin. The influence of the interlayer staggered zone C2 on the building is analyzed. Combined with the waterproof effect of current design scheme of anti-seepage curtain, the seepage field in the interlayer staggered zone C2 is discussed under different design schemes. The optimal design scheme of anti-seepage curtain is put forward. The results showed that the case four can effectively reduce the head and hydraulic gradient of underground powerhouse area, and improve the groundwater seepage field in the plant area.

Distribution characteristics of seepage field and prediction of water inflow before and after tunnel construction

In the construction of a deep tunnel with rich water and soft rock, accurate evaluations of the distribution characteristics of seepage field and water inflow are important bases for predicting the stability of tunnel surrounding rock and the disturbance state of groundwater environment. This paper used the Flac3D finite difference software seepage module, based on field geological borehole, measured seepage parameters and groundwater level. A three-dimensional numerical model of geological seepage in engineering area was established. The distribution characteristics of groundwater seepage field, the variation law of seepage field before and after tunnel excavation, and the water inflow during construction period were studied. As the tunnel was excavated, the excavated surface became a drainage channel, the isoline of groundwater pressure was changed into parallel non-parallel curve set by the parallel line of the initial seepage field. The nearer the tunnel centre was, the more obvious the variation tendency of groundwater pressure was. Grouting measures were very effective for tunnel water gushing, which not only reduced water inflow, but also effectively reduced the external water pressure of lining. It was infeasible to plug water when blocking the water without grouting and only adjusting the permeability of the lining.

Numerical Simulation of the Seepage Field and the Analysis of its Sensibility Based on Finite Element Method

The distribution characteristics and migration mechanism of seepage field of reservoir groundwater can determine the geographical characteristics of reservoir area to a large extent. The permeability of reservoir area is especially important since it is an important indicator of karst development characteristics and its hydrogeological condition in karst area, and it’s difficult to conduct quantitative analysis of its parameters. According to the needs of practical engineering application, I use the C# and FORTRAN program to design a calculation method. I also use seepage field numerical simulation in reservoir area of one pumped storage power station on the east to testify the correctness and practicability of this calculation method. Judging from the groundwater level contour map, we can see that groundwater shed and surface water shed are basically the same. Groundwater can be distributed to surrounding areas from the upper reservoir. Because of the resistance effect of non-karst area on north and south, groundwater flows out in the form of spring in north and south. The groundwater flows to Zimei Bridge on east side, and Yaoshiwan on west side. The repeated experiments of parameters show that groundwater seepage field is insensitive to the change of other areas’ permeability parameter. Results show that this calculation method is well-adapted, accurate, applicable and practical.

Analysis of Water-Rock Interaction and Two-Dimensional Seepage Field of Tunnel

Researches show that groundwater easily leads to tunnel disease. Groundwater seepage field is changed after the tunnel excavated. When crossing the fault fracture zone with groundwater, the tunnel will be cut into independent units with water. Along with the tensile stress on the tunnel invert and upper apex, it's prone to landslides and other damages. This paper analyzes the mechanism of interaction of water and rock, and describes the failure mechanism made by groundwater on the rock by RFPA2D, then analyzes the changes of groundwater seepage field before and after the tunnel excavation by using Rocscience Slide, finally the conventional Inflow prediction methods are contrasted.

The Groundwater Seepage Numerical Simulation and Prediction for a Alluvial Fan Water Resources Site

Based on the analysis of geological conditions of water resources site, generalized hydrological model was built, which was divided into three layers with different parameters. By using Visual Modflow, the groundwater seepage field was simulated for different mining yields, which give suggestions for the reasonable mining schedule of water resources site.

Research of Seepage Influence on the Lateral Water-Earth Pressure in Underground Structures

Earth pressure field and hydrostatic water pressure field are usually considered for classical earth pressure theories. Nonconsideration of groundwater seepage field is one of the main reasons why measured values of water-earth pressure on supporting structures are generally very different from those calculated values.Under the action of seepage,seepage force changes soil effective stress and affects soil shear strength.Through calculating the interraction of the hindering force field and seepage force field,a multi-field coupling problem is solved, a new calculation expressions on the foundation pit is presented.Key words : multi-field coupling; seepage ; lateral pressure ; water-earth pressure ; hindering force

Experimental Study of the Effect of Different Well Flow Quota on Groundwater Thermal Flow Transport Variation

In earth energy utilization, different multi-well flow match modes determine the different groundwater thermal flow transport characteristic. In this study, a laboratory experimental system was designed and set up to study the aquifer heat transfer performance and temperature field variation in different multi-well flow match modes. The experimental results show that under the condition of certain total flow rate, different multi-well flow match modes have great effects on the change of groundwater seepage field and temperature field. The bigger the flow rate, the greater the heat transfer per unit time and temperature field variation, and the closer the occurrence time between cold water frontal and cold water effect frontal, which is not conducive to the active control of aquifer temperature field.

Management of groundwater in Zhengzhou City, China

Quasi-three-dimensional numerical simulating and optimum management model was established for evaluating and managing groundwater resources in Zhengzhou city. Based on the coupling of simulating model with a planning model, an optimum management model of groundwater resource was established. Through optimum controlling of the groundwater seepage field, environmental problem caused by unreasonable extraction of groundwater in the study area was decreased to the minimum level, which supply scientific foundation for groundwater resource management in Zhengzhou city.