scholarly journals A Theoretical Calculation Method of Ground Settlement Based on a Groundwater Seepage and Drainage Model in Tunnel Engineering

2021 ◽  
Vol 13 (5) ◽  
pp. 2733
Author(s):  
Zhengde Wei ◽  
Yanpeng Zhu
Keyword(s):  
Effective Stress ◽  
Groundwater Level ◽  
Ground Deformation ◽  
Soil Layer ◽  
Seepage Flow ◽  
Gansu Province ◽  
Ground Settlement ◽  
Groundwater Seepage ◽  
Curve Equation

Seepage is ubiquitous during tunneling in areas with high groundwater tables. The ground settlement trough on a single tunnel is well described by Peck’s formula, but it cannot reflect the settlement caused by seepage. In this paper, assuming that the groundwater inside and outside the tunnel is a one-dimensional steady-state seepage condition, the groundwater seepage and drainage model of the tunnel was established. Based on the model and the principle of groundwater dynamics, the seepage flow calculation formula was derived, and the dewatering funnel curve equation of the groundwater level surface of a tunnel aquifer was obtained. A case study of a tunnel project in Gansu Province was carried out, and the influence of seepage on the effective stress of the stratum around the tunnel and the calculation of ground settlement caused by seepage were analyzed. The results show that seepage makes the effective stress of the upper soil layer of the tunnel increase, which leads to an increase in ground deformation; when the groundwater level of the tunnel is greatly lowered, the seepage has a significant influence on the vertical deformation of the stratum.

Detecting land deformation due to groundwater changes with InSAR observations - the case of the island of Gotland, Sweden

2021 ◽  
Author(s):  
Mehdi Darvishi ◽  
Fernando Jaramillo
Keyword(s):  
Land Subsidence ◽  
Groundwater Level ◽  
Ground Deformation ◽  
Soil Depth ◽  
Ground Surface ◽  
Groundwater Depletion ◽  
Groundwater Levels ◽  
Small Baseline Subset ◽  
Small Baseline ◽  
The Baltic

<p>In the recent years, southern Sweden has experienced drought conditions during the summer with potential risks of groundwater shortages. One of the main physical effects of groundwater depletion is land subsidence, a geohazard that potentially damages urban infrastructure, natural resources and can generate casualties. We here investigate land subsidence induced by groundwater depletion and/or seasonal variations in Gotland, an agricultural island in the Baltic Sea experiencing recent hydrological droughts in the summer. Taking advantage of the multiple monitoring groundwater wells active on the island, we explore the existence of a relationship between groundwater fluctuations and ground deformation, as obtained from Interferometric Synthetic Aperture Radar (InSAR). The aim in the long-term is to develop a high-accuracy map of land subsidence with an appropriate temporal and spatial resolution to understand groundwater changes in the area are recognize hydroclimatic and anthropogenic drivers of change.</p><p>We processed Sentinel-1 (S1) data, covering the time span of 2016-2019, by using the Small BAseline Subset (SBAS) to process 119 S1-A/B data (descending mode). The groundwater level of Nineteen wells distributed over the Gotland island were used to assess the relationship between groundwater depletion and the detected InSAR displacement. In addition to that, the roles of other geological key factors such as soil depth, ground capacity in bed rock, karstification, structure of bedrock and soil type in occurring land subsidence also investigated. The findings showed that the groundwater level in thirteen wells with soil depths of less than 5 meters correlated well with InSAR displacements. The closeness of bedrock to ground surface (small soil depth) was responsible for high coherence values near the wells, and enabled the detection land subsidence. The results demonstrated that InSAR could use as an effective monitoring system for groundwater management and can assist in predicting or estimating low groundwater levels during summer conditions.</p>

scholarly journals Fly Ash Modified Coalmine Solid Wastes for Stabilization of Trace Metals in Mining Damaged Land Reclamation: A Case Study in Xuzhou Coalmine Area

2018 ◽  
Vol 15 (10) ◽  
pp. 2317 ◽  
Author(s):  
Jiu Huang ◽  
Peng Wang ◽  
Chaorong Xu ◽  
Zhuangzhuang Zhu
Keyword(s):  
Fly Ash ◽  
Trace Metal ◽  
Soil Layer ◽  
Fly Ashes ◽  
Migration Ability ◽  
Metal Elements ◽  
Trace Metal Elements ◽  
Simulated Precipitation ◽  
Backfill Materials

In China, coalmine wastes, such as gangues, are used for reclamation of mining subsided land. However, as waste rocks, gangues contain several trace metal elements, which could be released under natural weathering and hydrodynamic leaching effects and then migrate into the reclamed soil layer. However, it is very difficult to find adequate other backfill materials for substitution of gangues. In this paper, we present a novel method and case study to restrict the migration ability of trace metal elements in gangues by using another kind of coalmine solid waste—fly ashes from coal combustion. In this study, fly ashes were mixed with gangues in different mass proportions 1:0.2, 1:0.4, 1:0.6 and 1:0.8 as new designed backfill materials. Due to the help of fly ash, the occurrence states of studied trace metal elements were greatly changed, and their releasing and migration ability under hydrodynamic leaching effect were also significantly restricted. In this research seven trace metal elements in gangues Cu, Zn, Pb, Cd, Cr, Mn and Ni were studied by using soil column hydrodynamical leaching method and simulated precipitation for one year. The results show that under the driving of natural precipitation trace metal elements were generally transported deep inside the reconstructed land base, i.e., far away from soil layer and most of the trace metal elements were transformed into a bonded state, or combined in inert occurrence states, especially the residual state. With this method, the migration activities of tested trace metal elements were greatly restricted and the environmental potential risk could be significantly reduced.

scholarly journals GIS development for ground deformation data management. A case study in Cephallonia island (western Greece)

2007 ◽  
Vol 40 (4) ◽  
pp. 2070 ◽  
Author(s):  
S. Vassilopoulou ◽  
K. Chousianitis ◽  
V. Sakkas ◽  
B. Damiata ◽  
E. Lagios
Keyword(s):  
Spatial Analysis ◽  
Data Management ◽  
Data Base ◽  
Crustal Deformation ◽  
Ground Deformation ◽  
Heterogeneous Data ◽  
Data Vector ◽  
Gis Data ◽  
Western Greece

The present study is concerned with the management of multi-thematic geo-data of Cephallonia Island, related to crustal deformation. A large amount of heterogeneous data (vector, raster, ascii files) involving geology, tectonics, topography, geomorphology and DGPS measurements was compiled. Crustal deformation was studied using GPS network consisting of '23 stations. This was installed and measured in October 2001 and re-measured during September 2003 following the Lefkas earthquake of August 2003 (Mw=6.2), and also in July 2006. With proper spatial analysis, a large number of thematic and synthetic layers and maps were produced. Simultaneously, a GIS Data base was organized in order to make an easy extraction of conclusions in specific questions.

scholarly journals On the transpiration of wild olives under water-limited conditions in a heterogeneous ecosystem with shallow soil over fractured rock

2020 ◽  
Vol 68 (4) ◽  
pp. 338-350
Author(s):  
Roberto Corona ◽  
Nicola Montaldo
Keyword(s):  
Fractured Rock ◽  
Soil Layer ◽  
Mediterranean Ecosystems ◽  
Adaptation Strategy ◽  
Tree Roots ◽  
Shallow Soil ◽  
Tree Transpiration ◽  
Dry Conditions ◽  
Wild Olive

AbstractMediterranean ecosystems are typically heterogeneous and savanna-like, with trees and grass competing for water use. By measuring sap flow, we estimated high transpiration of wild olive, a common Mediterranean tree, in Sardinia despite dry conditions. This estimate agrees with independent estimates of tree transpiration based on energy balance, highlighting the wild olive’s strong tolerance of dry conditions. The wild olive can develop an adaptation strategy to tolerate dry conditions. In this Sardinian case study, the wild olive grew in shallow soil, and the tree roots expanded into the underlying fractured basalt. The trees survived in dry periods using water infiltrated during wet seasons into fractured rocks and held in soil pockets. We estimated a high upward vertical flux through the bottom soil layer from the underlying substrate, which reached 97% evapotranspiration in August 2011. The water taken up by tree roots from bedrock hollows is usually neglected in ecohydrological modeling.

Economic Valuation of “Parak” Traditional Agroforestry West Sumatera (Case Study in Nagari Paninggahan, Solok Regency)

2021 ◽  
Vol 3 (3) ◽  
pp. 34-42
Author(s):  
Helmayuni ◽  
Mardianto
Keyword(s):  
Economic Valuation ◽  
Economic Value ◽  
Soil Layer ◽  
Secondary Data ◽  
Research Area ◽  
Primary Data ◽  
Domestic Water ◽  
Traditional Agroforestry ◽  
Direct Use

This study aims to determine the economic value, which is a direct and indirect benefit (tangible and intangible) of Parak in the research area. This research used a case study method, and the sampling was carried out in a purposive manner consisting of 50 sample farmers. The data used in this study are primary data and secondary data. Preliminary data were obtained by direct interviews with respondents based on the questionnaire provided, while secondary data were taken from agencies related to this research. The processing of data obtained in the field shows that Parak plays an important role in supporting the economy of farmers in Nagari Paninggahan either directly or indirectly. The direct use value obtained from the plant is IDR. 46,753,650 (66,316 per cent), from firewood of IDR. 23,070,000 (32,722 percent) and from livestock IDR. 678,550 (0.963 per cent) so that the total direct use income is IDR. 70,502,200 per year of all commodities cultivated by the sample farmers. Meanwhile, for indirect use, such as household/domestic water use, IDR. 13,312,320/year and agricultural irrigation water IDR. 54,052,111/year. The total indirect usage is IDR. 67,364,431,-. Per year. Agroforestry patterns can cover the soil layer well and have an effective influence on soil erosion control to increase the supply of water in the soil. Respondents have also carried out other conservation activities by constructing bench terraces, terracing systems, and other buildings to suppress sedimentation and erosion.

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