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1.
This paper presents a case study of the analysis and design of slopes for the portal of an underground crude oil storage cavern site. The site selected for the slope study is characterized by residual soils and granitic rock formations, located in the southwestern part of India. It is observed that in tropical residual soils, most hillslope failures are caused by rainfall and thus it is important to consider hydrological conditions when attempting to analyze the stability of slopes in such material. Combinations of shallow slopes with lower overburden and high steep hillslope with large overburden were considered in the present study along with varying combinations of lateritic soils and weathered rock formations. The paper discusses the various investigations carried out to define the geotechnical properties of lateritic soil and weathered rock, followed by numerical modelling and remedial measures adopted to ensure the stability of slopes during design and construction phase. Since analysis and design procedures for such residual soils are not well established, comprehensive geological and geotechnical investigations were carried out prior to numerical model development for carrying out finite element studies in order to ascertain long term stability of slopes under differing ground conditions. The results of the stability analysis indicated that slope under existing condition were potentially unstable under rainy conditions and specific supporting measures were planned to ensure stability. Several alternatives were examined for improving the stability of slope taking into consideration existing facilities, space available for mobilization of equipments and environmental conditions in reference to specific project requirements. The convergence pattern obtained from geotechnical monitoring using optical targets along the slopes did not showed any alarming movement for over a year. 相似文献
2.
This study evaluated remedial alternatives for a petroleum-contaminated site where an unconfined aquifer composed of a sandy layer of about 3–3.5 m thickness is covered by alluvial deposits and reclaimed soil of about 1.5 m thickness. Precambrian gneiss, of low permeability, lies below the sandy layer. The shallow water table is about 3 m below the surface, but shows high fluctuations of up to 1.5 m in response to precipitation events. The unsaturated soil near the water table and the groundwater are highly contaminated with petroleum hydrocarbons, especially toluene, which have apparently leaked from storage tanks. Selection of the remedial alternatives required consideration of the relevant laws on soil and groundwater conservation in Korea, the results of risk analysis and the hydrogeological conditions. The contaminated area has been divided into zones in which different remediation goals are set based on risk analysis and the degree of natural attenuation. It is estimated that the clean-up goal can be achieved in two years by the combined use of a trench drain and well point pumping to collect the contaminated groundwater for treatment, and a dual air injection system for the contaminated soil. 相似文献
3.
Natural Hazards - This study aims to examine a set of alternatives as remedial measures for the flood management purposes in order to protect the northern part of Nicosia which has been affected by... 相似文献
4.
A numerical groundwater flow and mass transport model was developed to predict the extent of impact from methyl tertiary butyl
ether (MTBE) release on a down-gradient drinking water well field. An MTBE incident in Pascoag, Rhode Island, was used as
a case study and the plume’s past and future development was simulated using scenario analysis. The numerical code used was
GeoSys/Rockflow, which permits a coupled flow and transport simulation as one object, thus alleviating the need for simulating
the MTBE fate with separate flow and transport codes. The numerical model was built on available hydrogeological and chemical
data as well as on GIS information of the site. By comparing the simulated results with observed field data, it was found
that the model could provide reliable results even when the simulated aquifer was simplified to a two-dimensional flow and
transport domain. Finally, the calibrated model was used for exploring a location that may be suitable for a new well field.
Despite the model limitations associated with uncertainties of data and simplifying assumptions, numerical modeling of this
MTBE contaminated site proved a useful tool and provided guidance for future municipal well field operation strategies and
aquifer remediation alternatives. 相似文献
5.
Landslips are often triggered due to non-engineered excavation of potential unstable slopes. Such slips can be stabilized by implementing suitable remedial measures.A landslip occurred at a drilling site of Oil India Limited in Mizoram State due to slope excavation. There was an immediate concern to protect the slope as the drilling platform and the highway at the top of the slope are at risk if further landslide occurs in future. Slope stability analysis of the failed slope was carried out to design suitable control measures for the protection of the slope from further sliding. Slope stability using various methods indicated that the slope is marginally stable. To improve the stability of the slope, suitable retaining structure at the toe of the slope was suggested and designed. Stability analysis performed with inclusion of retaining wall showed a significant increase in factor of safety of the slope. The suggested remedial measure has been implemented at the site and there is no landslip reported since then. The paper presents the results of the slope stability analysis and the design details of the retaining structure prescribed as the protection measure. 相似文献
6.
In this paper, the authors present a probabilistic back-analysis of a recent slope failure at a site on Freeway No. 3 in northern Taiwan. Post-event investigations of this failure found uncertain strength parameters and deteriorating anchor systems as the most likely causes for failure. Field measurement after the event indicated an average slip surface of inclination 15°. To account for the uncertainties in input parameters, the probabilistic back analysis approach was adopted. First, the Markov Chain Monte Carlo (MCMC) simulation was used to back-calculate the geotechnical strength parameters and the anchor force. These inverse analysis results, which agreed closely with the findings of the post-event investigations, were then used to validate the maximum likelihood (ML) method, a computationally more efficient back-analysis approach. The improved knowledge of the geotechnical strength parameters and the anchor force gained through the probabilistic inverse analysis better elucidated the slope failure mechanism, which provides a basis for a more rational selection of remedial measures. 相似文献
7.
Slope failure or landslide is a complex geological/geotechnical problem that involves much uncertainty. In this work, a framework for probabilistic assessment of landslide is presented with a focus on the El Berrinche landslide, Honduras. One unique feature of this case study involving the El Berrinche landslide is that the stability analysis has to be carried out with limited data. Another challenge in this study is to assess possible remedial measures in a way that can easily be communicated to the government and the public. A reliability-based framework for a probabilistic assessment is proposed. With this approach, different levels of risk for landslide are assessed and the associated costs are estimated; and all information is integrated into the decision-making process for choosing a remedial action. 相似文献
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城市中心密集建筑群使得地铁需长距离穿越既有建（构）筑物,导致地面管井施工作业条件越来越难,降水沉降控制要求也越来越严。从轨道交通工程建设出发,当受施工场地限制时,提出在导洞内施工管井,并对降水导洞的设计、成井机械及施工工法进行了论述。针对施工降水引起的附加沉降,采用地下水三维渗流与地面沉降耦合模型计算软件——Pro-cessing Modflow,建立地下水流场与地面沉降的耦合模型,根据现场监测数据,运用参数修正后的模型,设计不同的抽降方案,分时段进行沉降预测,及时分析施工降水对周围环境的影响程度,可指导类似工程施工,具有重要的工程实际意义。 相似文献
10.
滑坡及危岩(崩塌)防治工程措施选择与工程设置 总被引：6，自引：1，他引：6
滑坡和危岩（崩塌）治理工程措施较多，措施组合可变性大，每种工程措施都有其相应的应用条件，不宜性、适宜性和最佳配置组合。治理工程措施选择应充分考虑治理工程功能性的具体要求、在不同工况条件下的安全性及耐久性、工期要求和投资的经济性以及后期维护的要求、工程岩土体性质及其蓄水后的变化、场地条件、施工技术条件、地方材料资源等具体制约因素以及环境保护的要求。在三峡水库区二期地质灾害防治工程国家级验收总结的基础上，对滑坡与危岩（崩塌）常用防治工程措施（排水、削方减载、回填压脚、抗滑桩、重力式抗滑挡墙、预应力锚索、格构锚固、拦石墙等）的工程适用条件、工程设置及不宜性进行了详细的分析，并提出工程设置应考虑及注意的问题。 相似文献
11.
Extensive research has been done on investigation, monitoring, risk evaluation and land management to prevent formation of sinkholes and subsidences in karst terranes. Little emphasis is, however, given to the various processes and methodologies with respect to their remediation. Sinkholes are a surface symptom of complicated erosion and deformation processes that occur on the surface and in the subsurface. The specific method or combination of methods used to mitigate a sinkhole or subsidence depends on the complexity of the conceptual site model composed of influencing factors and triggering mechanisms, depth and lateral extent of instability, impact on existing infrastructure, and existing and reasonably anticipated land uses. Many sinkhole and subsidence rehabilitation methods including dynamic compaction, construction of inverted filters, compaction grouting and construction of water plugs are presented; however, each sinkhole must be treated uniquely when a decision is made on the most appropriate rehabilitation method. A case study was presented to illustrate how the conceptual site model and remedial alternative analysis approach were used to determine the preferred method for sinkhole remediation. 相似文献
12.
Velocity attenuation of debris flows and a new momentum-based load model for rigid barriers 总被引：2，自引：1，他引：1
R. C. H. Koo J. S. H. Kwan C. W. W. Ng C. Lam C. E. Choi D. Song W. K. Pun 《Landslides》2017,14(2):617-629
Effective design of mitigation measures against debris flow hazards remains a challenging geotechnical problem. At present, a pseudo-static approach is commonly used for the calculation of impact load acting on a rigid debris-resisting barrier. The impact load is normally calculated based on the maximum velocity observed in the transportation zone under free-field conditions without considering debris-barrier interaction. In reality, the impact load acting on a barrier varies with the change of debris momentum flux but this is seldom considered in barrier design. To provide a scientific basis for assessing debris momentum flux during impact, this paper presents results from a study of debris-barrier interaction using physical flume modelling. This study showed that, following the first stage of impact, the accumulated debris behind a barrier formed a stationary zone and caused the remaining debris to slow down in a run-up process. In the experiments, the peak debris momentum was 30 % lower compared to that observed under free-field conditions. A new momentum-based model was developed to take into account attenuation of momentum flux for predicting debris impact load on rigid barriers. The new rationalised model was assessed using data from the notable Yu Tung Road debris flow in Hong Kong. The assessment showed that the design bending moment at the base of the barrier wall could be reduced more than 30 % using the proposed model, compared with the current design approach. The adoption of the proposed model could offer a new opportunity for practitioners to optimise the design of rigid barriers. 相似文献
13.
T. K. S. Abam 《Environmental Geology》1997,31(3-4):211-220
The recession of alluvial channel banks occurs as a sequence of mass movements or by gradual dissolution of bank materials.
Criteria for recognizing and interpreting bank recessions due to mass movement and/or erosion are presented. Using back analysis
technique, slope development processes are reconstructed as a sequence of bank failure episodes and erosional events. Various
mechanisms of mass bank failure and recession as well as causative agents have been identified and analyzed. A deterministic
sensitivity technique based on partial differentiation can be used for evaluating the contribution of factors to bank recession
and as a basis for selecting bank erosion remedial measures.
Received: 15 September 1995 · Accepted: 23 January 1996 相似文献
14.
Tsu-Chiang Lei Shiuan Wan Tien-Yin Chou Hung-Chieh Pai 《Environmental Earth Sciences》2011,63(5):981-997
Debris flow is often performed through identifying and analyzing the soil condition, hydraulic, geomorphological factors and
vegetation conditions. In the present study, a spatial information analysis system is combined with a linear statistical method
(principle components analysis with linear discriminant analysis, PCA + LDA) and an advanced data mining technique (discrete
rough sets, DRS) to investigate the debris flow occurrence based on geomorphological and vegetation conditions factors. The
analyzed data sources include (1) digital elevation model: to investigate the variation in the landscape, and (2) remote sensing
data: to analyze the vegetation and plant conditions on the ground surface. The objective of this research is to define a
method with the ability to forecast the level of debris flow susceptibility through the parallel study of statistical outcomes
(PCA + LDA) and data mining results (DRS). The outcomes from PCA + LDA are inadequate due to the thresholds of the influenced
variables not being examined. In this study, the DRS approach not only showed satisfactory results for the thresholds of influenced
variables in the study area, but also the occurrence rules of debris flow are generated. Finally, the results show superior
classification accuracy (70.8% for debris flow occurrence) for the DRS method over those of PCA + LDA analysis (54.2% for
debris flow occurrence) for the analysis of debris flow occurrence. Therefore, this is an encouraging preliminary approach
in the hazard assessment of debris flow. 相似文献
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16.
Jo Eidsvik Geetartha Dutta Tapan Mukerji Debarun Bhattacharjya 《Mathematical Geosciences》2017,49(4):467-491
Value of information analysis is useful for helping a decision maker evaluate the benefits of acquiring or processing additional data. Such analysis is particularly beneficial in the petroleum industry, where information gathering is costly and time-consuming. Furthermore, there are often abundant opportunities for discovering creative information gathering schemes, involving the type and location of geophysical measurements. A consistent evaluation of such data requires spatial modeling that realistically captures the various aspects of the decision situation: the uncertain reservoir variables, the alternatives and the geophysical data under consideration. The computational tasks of value of information analysis can be daunting in such spatial decision situations; in this paper, a regression-based approximation approach is presented. The approach involves Monte Carlo simulation of data followed by linear regression to fit the conditional expectation expression that is needed for value of information analysis. Efficient approximations allow practical value of information analysis for the spatial decision situations that are typically encountered in petroleum reservoir evaluation. Applications are presented for seismic amplitude data and electromagnetic resistivity data, where one example includes multi-phase fluid flow simulations. 相似文献
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18.
In this paper, we study the properties of approximate solutions to a doubly nonlinear and degenerate diffusion equation, known
in the literature as the diffusive wave approximation of the shallow water equations (DSW), using a numerical approach based
on the Galerkin finite element method. This equation arises in shallow water flow models when special assumptions are used
to simplify the shallow water equations and contains as particular cases the porous medium equation and the p-Laplacian. Diverse
numerical schemes have been implemented to approximately solve the DSW equation and have been successfully applied as suitable
models to simulate overland flow and water flow in vegetated areas such as wetlands; yet, no formal mathematical analysis
has been carried out in order to study the properties of approximate solutions. In this study, we propose a numerical approach
as a means to understand some properties of solutions to the DSW equation and, thus, to provide conditions for which the use
of the DSW equation may be inappropriate from both the physical and the mathematical points of view, within the context of
shallow water modeling. For analysis purposes, we propose a numerical method based on the Galerkin method and we obtain a
priori error estimates between the approximate solutions and weak solutions to the DSW equation under physically consistent
assumptions. We also present some numerical experiments that provide relevant information about the accuracy of the proposed
numerical method to solve the DSW equation and the applicability of the DSW equation as a model to simulate observed quantities
in an experimental setting. 相似文献
19.
Cost-benefit analysis can be used to identify the optimum remedial strategy for contaminated groundwater, but requires that the benefits of remedial action be quantified. When the groundwater is located in an unused part of an aquifer, it can be difficult to estimate the economic loss of resource. ‘Option values’, which represent the value placed on groundwater for possible future use, may be used. Calculation of the overall loss requires consideration of the spatial (physical) extent of an aquifer where groundwater use is constrained by the presence of contamination and economic elements. An approach is presented for estimating the spatial element, represented as the annualised abstraction loss from the groundwater resource. Two distinct components have been identified based on the potential restriction on location of a new abstraction well: (1) the direct resource loss, which relates to the contaminated zone of the aquifer within which new abstraction is no longer an option, and, (2) the indirect location loss, which relates to the loss of an opportunity to site a new abstraction well in the surrounding uncontaminated aquifer due to the presence of the plume. Methods are presented for their calculation and the approach is illustrated with a case study. 相似文献
20.
本文介绍了天福庙拱坝坝肩岩体稳定性研究,并提出了相应加固措施的建议。即在详尽的工程地质水文地质调查的基础上分析出各种可能的失稳机制,并组合出各种滑移边界条件;通过现场和室内岩体力学试验,测出构成边界条件的各种地质结构面的抗剪强度和变形常数;通过三维有限元弹性分析计算,得到应力应变和破损区的分布,检验了失稳机制和边界条件的合理性;通过刚体极限平衡法,计算出各种荷载和边界条件组合情况下的抗滑稳定安全系数;尔后针对最不稳定边界条件及其控制稳定性的主要因素,提出有效的加固措施的建议。文中还讨论了岩体和各种软弱结构面抗剪强度的取值原则、试验值的使用原则以及非均质结构面和组合结构面的综合抗剪强度问题。 相似文献