Influence of Variation of Groundwater Level on Deformation of Subgrade Based on Hydromechanical Coupling

2012 ◽  
Vol 457-458 ◽  
pp. 30-33
Author(s):  
Meng Ling Hu ◽  
Hai Lin Yao ◽  
Jie Liu ◽  
Zheng Lu
Keyword(s):  
Water Content ◽  
Water Level ◽  
Groundwater Level ◽  
Laboratory Tests ◽  
Resilient Modulus ◽  
Great Influence ◽  
Coupling Mechanism ◽  
Hydromechanical Coupling ◽  
Subgrade Soil ◽  
The Relationship

Deformation of subgrade caused by variation of groundwater level is a problem of hydromechanical coupling. The coupling mechanism of seepage and deformation of subgrade was analyzed, and a model of hydromechanical coupling was then established. The resilient modulus of the model is related to the water content and compactness of subgrade soil. The relationship between them was obtained based on laboratory tests, and was employed to research the influence of rise of groundwater level on resilient modulus and deformation of subgrade. The results showed that the rise of water level had great influence on resilient modulus of subgrade, and the deformation of subgrade can’t be neglected.

Study on Roadbed Soil Dynamic Resilient Modulus Test

2013 ◽  
Vol 671-674 ◽  
pp. 1245-1253 ◽  
Author(s):  
An Hua Xu ◽  
Jian Hong Fang
Keyword(s):  
Water Content ◽  
Test Data ◽  
Data Model ◽  
Resilient Modulus ◽  
Forecast Model ◽  
Deviatoric Stress ◽  
Triaxial Tests ◽  
Subgrade Soil ◽  
The Relationship ◽  
Soil Dynamic

This paper draws on the successful experience from domestic and abroad researches, testing repeatedly of powder subgrade with load triaxial tests, analyzing the relationship between the subgrade soil resilient modulus, deviatoric stress, water content and degree of compaction. At the same time, conducting corresponded roadbed soil resilient modulus forecast model, and qualifying its correctness of test data model.

scholarly journals Characterising hillslope–stream connectivity with a joint event analysis of stream and groundwater levels

2020 ◽  
Vol 24 (12) ◽  
pp. 5713-5744
Author(s):  
Daniel Beiter ◽  
Markus Weiler ◽  
Theresa Blume
Keyword(s):  
Time Series ◽  
Water Level ◽  
Groundwater Level ◽  
Stream Water ◽  
Water Levels ◽  
Joint Analysis ◽  
Strong Increase ◽  
Groundwater Levels ◽  
The Relationship ◽  
Insight Into

Abstract. Hillslope–stream connectivity controls runoff generation, during events and during baseflow conditions. However, assessing subsurface connectivity is a challenging task, as it occurs in the hidden subsurface domain where water flow can not be easily observed. We therefore investigated if the results of a joint analysis of rainfall event responses of near-stream groundwater levels and stream water levels could serve as a viable proxy for hillslope–stream connectivity. The analysis focuses on the extent of response, correlations, lag times and synchronicity. As a first step, a new data analysis scheme was developed, separating the aspects of (a) response timing and (b) extent of water level change. This provides new perspectives on the relationship between groundwater and stream responses. In a second step we investigated if this analysis can give an indication of hillslope–stream connectivity at the catchment scale. Stream water levels and groundwater levels were measured at five different hillslopes over 5 to 6 years. Using a new detection algorithm, we extracted 706 rainfall response events for subsequent analysis. Carrying out this analysis in two different geological regions (schist and marls) allowed us to test the usefulness of the proxy under different hydrological settings while also providing insight into the geologically driven differences in response behaviour. For rainfall events with low initial groundwater level, groundwater level responses often lag behind the stream with respect to the start of rise and the time of peak. This lag disappears at high antecedent groundwater levels. At low groundwater levels the relationship between groundwater and stream water level responses to rainfall are highly variable, while at high groundwater levels, above a certain threshold, this relationship tends to become more uniform. The same threshold was able to predict increased likelihood for high runoff coefficients, indicating a strong increase in connectivity once the groundwater level threshold was surpassed. The joint analysis of shallow near-stream groundwater and stream water levels provided information on the presence or absence and to a certain extent also on the degree of subsurface hillslope–stream connectivity. The underlying threshold processes were interpreted as transmissivity feedback in the marls and fill-and-spill in the schist. The value of these measurements is high; however, time series of several years and a large number of events are necessary to produce representative results. We also find that locally measured thresholds in groundwater levels can provide insight into the connectivity and event response of the corresponding headwater catchments. If the location of the well is chosen wisely, a single time series of shallow groundwater can indicate if the catchment is in a state of high or low connectivity.

scholarly journals Analisis Pengaruh Fluktuasi Muka Air Waduk terhadap Stabilitas Lereng Waduk Dengan Menggunakan Program Plaxis 2D

2019 ◽  
Vol 24 (2) ◽  
pp. 113
Author(s):  
Paravita Sri Wulandari ◽  
Daniel Tjandra
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Water Level ◽  
Laboratory Tests ◽  
Slope Failure ◽  
Soil Characteristics ◽  
Soil Samples ◽  
Initial Condition ◽  
Soil Shear Strength ◽  
Influence Of Water

Reservoir is needed as a source of water supply to the surrounding populations. The design of a reservoir needs to consider several aspects of soil embankment such as variations in water content and changes in shear soil shear strength and also the influence of water level in reservoir. The purpose of this research is to analyze these three aspects in the design of a reservoir. This research was begun by taking soil samples for embankment and conducting soil tests to obtain soil characteristics at the initial condition. The further laboratory tests were conducted to determine the effect of changes in water content on the shear strength of the soil. The variation of soil embankment characteristic was then modeled by Plaxis 2D program to obtain the effect of changes in soil embankment characteristic and fluctuation of the water level in the reservoir. The results showed that the increase in water content significantly decrease the shear strength of the soil. The changes of soil shear strength affect the pattern of slope failure and safety factor. In addition, the pattern and direction of the slope failure were also influenced by the water level of the reservoir.

Analysis of the Influence of Water Content on Shanxi Loess CBR and Rebound Module

2014 ◽  
Vol 919-921 ◽  
pp. 820-823
Author(s):  
Xi Rong Wu ◽  
Li Li Zhu
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Resilient Modulus ◽  
Test Methods ◽  
Shanxi Province ◽  
Influence Of Water ◽  
The Times ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

Selection of five typical loess in Shanxi Province, the paper adopt the indoor test methods to prepares the different compaction and different moisture content specimens which were used to test CBR value and rebound module, analyzes the impact of compactness and moisture content on the CBR value and resilient modulus and establishes the relationship of CBR and moisture content. The result shows that the level of moisture content has great impact on CBR value and rebound module. The CBR value is maximal under optimum moisture content and maximum degree of compaction condition. The times of compaction have little effect on the improvement of CBR with increasing water content. The relationship of the soaking CBR,resilient modulus and the moisture content shows a certain regularity.Key words: Loess filler;the CBR;resilient modulus;compactness;moisture content;relationship

scholarly journals Characterizing hillslope-stream connectivity with a joint event analysis of stream and groundwater levels

2020 ◽  
Author(s):  
Daniel Beiter ◽  
Markus Weiler ◽  
Theresa Blume
Keyword(s):  
Time Series ◽  
Water Level ◽  
Groundwater Level ◽  
Stream Water ◽  
Water Levels ◽  
Joint Analysis ◽  
Catchment Scale ◽  
Groundwater Levels ◽  
The Relationship ◽  
Insight Into

Abstract. Hillslope-stream connectivity controls runoff generation, both during events and baseflow conditions. However, assessing subsurface connectivity is a challenging task, as it occurs in the hidden subsurface domain where water flow cannot be easily observed. We therefore investigated if the results of a joint analysis of rainfall event responses of near-stream groundwater levels and stream water levels could serve as a viable proxy for hillslope-stream connectivity. The analysis focuses on the extent of response, correlations, lag times and synchronicity. A newly developed data analysis scheme of separating the aspects of (a) response timing and (b) extent of water level change provides new perspectives on the relationship between groundwater and stream responses. In a second step we investigated if this analysis can give an indication of hillslope-stream connectivity at the catchment scale. Stream- and groundwater levels were measured at five different hillslopes over 5 to 6 years. Using a new detection algorithm we extracted 706 rainfall response events for subsequent analysis. Carrying out this analysis in two different geological regions (schist and marls) allowed us to test the usefulness of the proxy under different hydrological settings while also providing insight into the geologically-driven differences in response behaviour. For rainfall events with low initial groundwater level, groundwater level responses often lag behind the stream with respect to the start of rise and the time of peak. This lag disappears at high antecedent groundwater levels. At low groundwater levels the relationship between groundwater and stream water level responses to rainfall are highly variable, while at high groundwater levels, above a certain threshold, this relationship tends to become more uniform. The same threshold was able to predict increased likelihood for high runoff coefficients, indicating a strong increase in connectivity once the groundwater level threshold was surpassed. The joint analysis of shallow near-stream groundwater and stream water levels provided information on the presence or absence and to a certain extent also on the degree of subsurface hillslope-stream connectivity. The underlying threshold processes were interpreted as transmissivity feedback in the marls and fill-and-spill in the schist. The value of these measurements is high, however, time series of several years and a large number of events are necessary to produce representative results. We also find that locally measured thresholds in groundwater levels can provide insight into catchment-scale connectivity and event response. If the location of the well is chosen wisely, a single time series of shallow groundwater can indicate if the catchment is in a state of high or low connectivity.

scholarly journals Effects of Groundwater Level on the Occurrence of Forest and Peatland Fires: A Case of Study in Musi Banyuasin Regency

2020 ◽  
Vol 8 (2) ◽  
pp. 173
Author(s):  
Denni Prasetia ◽  
Wahyu Hidayat ◽  
Lailan Syaufina
Keyword(s):  
Ground Water ◽  
Water Level ◽  
Forest Fire ◽  
Forest Fires ◽  
Groundwater Level ◽  
Inverse Relationship ◽  
Rainfall Data ◽  
Ground Water Level ◽  
Bivariate Correlation ◽  
The Relationship

Ground water level (GWL) is one of the indicators to predict potential fires on peatlands. Other factors, such as rainfall and hotspots, could also trigger peatland and forest fires. This study aimed to analyze the relationship between rainfall GWL, rainfall, and hotspots as indicators of forest and land fires in Musi Banyuasin Regency, South Sumatra Province. The GWL data, hotspot distribution, rainfall data were processed using ArcGIS 10.6 software. Pearson bivariate correlation test was performed to determine the relationship between GWL, hotspot distribution, and rainfall. The results showed a decrease in rainfall, followed by an increase in hotspots, particularly during the dry season. The lowest rainfall and GWL occurred in July – August 2018. The increase in rainfall was not followed by the GWL increase that reflected a degraded and dry peatland condition, which could cause a decrease of peat ability to absorb and store water properly. The results also showed an inverse relationship between hotspots and GWL, which means that a decrease in the GWL will follow the increase in hotspots and vice versa. This explains that the increase of hotspots contributed to a drought on the GWL of the peatlands. Keywords: ground water level, forest fire, hotspot, Musi Banyuasin, peatland, rainfall

Study on the Relations of Strength Control Indicators of Road Subgrade in Shanxi Loess Region

2014 ◽  
Vol 919-921 ◽  
pp. 1160-1163
Author(s):  
Xi Rong Wu ◽  
Li Li Zhu
Keyword(s):  
Moisture Content ◽  
Key Words ◽  
Water Content ◽  
Test Section ◽  
Laboratory Experiments ◽  
Resilient Modulus ◽  
Poor Correlation ◽  
Bearing Plate ◽  
Loess Region ◽  
The Relationship

Typical loess areas of Shanxi test section as the basis, through on-site tests, the paper presents the relationship between filed CBR, compaction,moisture content and on-site bearing plate modulus. Through laboratory experiments, the paper examines the variation of resilient modulus and CBR in different water content and degree of compaction conditions. The correlation between site and interior strength indicators was analyzed and the result shows that indicators tested in laboratory have good correlation while indicators tested in field have poor correlation. Key words: loess; rebound modules; CBR; moisture content;compaction; correlation

scholarly journals A New Remote Sensing Index for Assessing the Spatial Heterogeneity in Urban Eco-Environmental Quality Associated Road Network

2021 ◽  
Author(s):  
Xincheng Zheng ◽  
Zeyao Zou ◽  
Chongmin Xu ◽  
Sen Lin ◽  
Zhilong Wu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Spatial Variation ◽  
Environmental Quality ◽  
Land Surface ◽  
Road Network ◽  
Great Influence ◽  
Bare Soil ◽  
Coupling Mechanism ◽  
The Road ◽  
The Relationship

Abstract Although many prior efforts have found that road network has significantly affect the landscape fragmentation, the spatially heterogeneous effects of road network on the urban eco-environment remain poorly understood. To understanding the coupling mechanism of road network and eco-environment, a new remote sensing based ecological index (RSEI) was proposed to calculate the eco-environment quality, and kernel density of road (KDR) was applied to measure the road network density. We proposed a spatially explicit approach (geographically weighted regression, GWR) to explore the spatial variations in the relationship between the road network and the eco-environmental quality The results of GWR models fit better than those of the Ordinary Least Square (OLS) models. Among, the average effect of KDR on the variables of normalized difference vegetation index, land surface moisture and RSEI was negative, while it was positively associated with the variables of soil index, normalized differential build-up and bare soil index, index-based built-up index, and land surface temperature. From spatial perspective, the impacts of KDR on the urban boundary were generally greater than those on the city center. The spatial variation in the relationship between the road network and the eco-environment is mainly controlled by the relationship between the road network to the vegetation and the bare soil. Locally, the water body, whether a large regional river or urban inland rivers, has a great influence on the spatial variation in the relationship between the roads and the eco-environmental variables, and it can even change the sign of the influence.

scholarly journals Model Penurunan Tinggi Muka Air Tanah Setelah Kejadian Hujan di Lokasi Sistem Peringatan Dini Longsor di Kampung Jatiradio, Desa Cililin, Kecamatan Cililin, Kabupaten Bandung Barat

2020 ◽  
Vol 4 (1) ◽  
pp. 1-8
Author(s):  
Mr Prihartanto
Keyword(s):  
Regression Model ◽  
Ground Water ◽  
Water Level ◽  
Early Warning ◽  
Groundwater Level ◽  
Early Warning System ◽  
Warning System ◽  
Ground Water Level ◽  
Landslide Early Warning ◽  
The Relationship

AbstractLandslide events that have occurred  in Jatiradio, Cililin Village, Cililin District, West Bandung Regency triggered the installation of a Landslide Early Warning System (LEWS). The equipmentl transmits data such as rainfall and ground water level for every hour which is detected from rain gauge sensors and pressure transducers. The relationship between rainfall and ground water level is important to understand in order to know the fluctuttion patterns that trigger landslides. Therefore, mathematical model of the decline in groundwater level every time after the rainfall in Jatiradio, Cililin Village, Cililin District, West Bandung Regency during the 2019 rainy season was made. Thus, it can be seen the relationship between rainfall patterns and water level fluctuations in certain rainfall periods.The method used in producing the model is a regression model using spreedsheet software. Regression equations and coefficients of determination were obtained to analyze the relationship of ground water level to rainfall. The results of mathematical modeling between ground level I (23-24 February 2019) and II (24-25 February 2019) are linear to rainfall, except for the decline in groundwater level III which occurred on February 25-28, 2019 which shows exponential relationship, meaning that a rapid decline in groundwater level. The regression model equation obtained for each groundwater level decrease is  with R² = 0.9631;  with R² = 0.9988;  with R2 = 0.9903. Keywords: Model, Landslide, Landslide Early Warning System, PreparednessAbstrakKejadian bencana longsor yang pernah terjadi di Kampung Jatiradio, Desa Cililin, Kecamatan Cililin, Kabupaten Bandung Barat mendorong dipasangnya alat Landslide Early Warning System (LEWS). Alat tersebut mengirimkan data seperti curah hujan dan tinggi muka air tanah setiap satu jam yang dideteksi dari sensor penakar hujan dan pressure transducer. Hubungan antara curah hujan dan tinggi muka air tanah penting untuk diketahui agar dapat diketahui pola fluktuasi yang memicu longsor. Maka dari itu membuat model matematik penurunan tinggi muka air tanah setiap kali setelah kejadian hujan di Kampung Jatiradio, Desa Cililin, Kecamatan Cililin, Kabupaten Bandung Barat pada saat musim hujan 2019. Model penurunan tinggi muka air tersebut dapat dihubungkan dengan pola fluktuasi curah hujan yang terjadi dengan demikian dapat diketahui hubungan antara pola curah hujan dan pola fluktuasi tinggi muka air pada periode hujan tertentu.Metode yang digunakan dalam menghasilkan model tersebut yaitu model regresi dengan menggunakan perangkat lunak spreedsheet. Persamaan regresi dan koefisien determinasi didapatkan untuk menganalisis hubungan tinggi muka air tanah terhadap curah hujan. Hasil pemodelan matematika menghasilkan hubungan penurunan tinggi muka air tanah I (23 – 24 Februari 2019) dan II (24-25 Februari 2019) linier terhadap curah hujan, kecuali penurunan tinggi muka air tanah III yang terjadi pada tanggal 25-28 Februari 2019 yang menunjukkan hubungan eksponensial, artinya terjadi penurunan tinggi muka air tanah yang cepat. Persamaan model regresi yang didapatkan untuk masing-masing penurunan yaitu  dengan R² = 0,9631 ; dengan R² = 0,9988;  dengan R² = 0,9903. Kata kunci: Model, Longsor, Sistem Peringatan Dini Longsor, Kesiapsiagaan

SOIL WATER CHARACTERISTIC CURVES OF COMPACTED KAOLIN FOR VARIOUS INITIAL MOISTURE CONTENT

2015 ◽  
Vol 76 (2) ◽  
Author(s):  
Muhammad Azril Hezmi ◽  
Radzuan Saari ◽  
Mohd Zakri Zahari ◽  
Rini Asnida Abdullah ◽  
Nor Zurairahetty Mohd Yunus ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Filter Paper ◽  
Unsaturated Soils ◽  
Initial Moisture Content ◽  
Great Influence ◽  
Water Retention Curve ◽  
Initial Water Content ◽  
Initial Water ◽  
The Relationship

The soil water characteristic curve (SWCC), also known as soil water retention curve (SWRC), describes the relationship between water content and soil suction in unsaturated soils. The importance of SWCC can be seen, as the relationship affects geotechnical properties such as shear strength, volume change, permeability and deformability of unsaturated soils. This paper presented a preliminary study on the effect of initial water content and the density on SWCC on unsaturated compacted kaolin. Filter paper technique was used for suction measurement on the unsaturated compacted kaolin soil. Filter paper was used to determine total suction and matric suction through contact and noncontact technique. The calibration curve was used to relate with the gravimetric water content obtained in filter paper with corresponding suction. A comparison on SWCC established through filter paper was also compared with that of the axis translation technique (pressure plate extractor). The study found that the initial water content and the density respectively, have great influence on the SWCC of compacted kaolin. However, the combined effect could be seen significantly at lower suction

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