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Slope inclinometers for landslides 总被引：2，自引：1，他引：1
Slope inclinometers/indicators are used to determine the magnitude, rate, direction, depth, and type of landslide movement.
This information is usually vitally important for understanding the cause, behavior, and remediation of a landslide. However,
many inclinometer measurements fail to achieve these intended aims because of lack of appreciation of the many factors that
need to be correctly implemented during installation, monitoring, and data reduction to yield useful data. This paper presents
some guidelines for understanding, installing, and interpreting slope inclinometers and presents three case histories that
illustrate some of the pitfalls that can develop if these guidelines are not followed. 相似文献
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An analysis method for transient groundwater flow during slug tests performed in vertical cutoff walls is presented. The analytical solution for evaluating hydraulic conductivity of vertical cutoff walls is derived by applying the method of images to the previously developed analytical solution that is exclusively applicable to an infinite aquifer. Two distinct boundary conditions are considered to account for the configuration of the vertical cutoff wall: the wall‐soil formation interfaces with or without the existence of filter cakes, that is, constant‐head boundary and no‐flux boundary conditions. A series of type curves is constructed from the analytical solution and compared with those of a partially penetrated well within an aquifer. The constant‐head boundary condition provides faster hydraulic head recovery than the aquifer case. On the other hand, the no‐flux boundary condition leads to a delayed hydraulic head recovery. The greater the shape factor and well offset from the center of the cutoff wall, and the smaller the width of the cutoff wall, the greater the effect of the boundary condition observed in the type curves. This result shows the significance of considering proper boundary conditions at the vertical cutoff wall in analyzing slug tests. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Lee Seokjae Yang Subin Lee Dongjoon Choi Hangseok Won Jongmuk 《Hydrogeology Journal》2023,31(5):1245-1257
Understanding contaminant transport in clay-containing soils is critical for accurate prediction of the travel distances of contaminants and for the design and implementation of corresponding remediation plans. This study examined the breakthrough behavior of methylene blue (MB) through sand-illite mixtures using laboratory soil-column experiments at five inlet concentrations, three flow rates, and five illite contents. Kinetic and equilibrium adsorption tests were performed to evaluate the maximum adsorption capacities of the sand and illite used in the soil-column experiments. In addition, the bed efficiency, MB saturation, and adsorption rate were calculated to quantitatively describe the observed breakthrough curves. The observed breakthrough curves, bed efficiencies, MB saturations, and adsorption rates in this study demonstrated the presence of a threshold illite content of ~10% for the adsorption efficiency of contaminants. This implies the need to evaluate the threshold clay content for accurate predictions of contaminant transport through gap-graded clay-containing soils.
相似文献4.
An analysis method for slug tests performed in a partially penetrating well within a vertical cutoff wall is presented. A steady‐state shape factor for evaluating hydraulic conductivity of the material within the wall was derived by applying the method of images to the previously developed analytical solution of Zlotnik et al. (2010) for an infinite aquifer. Two distinct boundary conditions were considered: constant‐head boundary for the case of direct contact between the wall and the aquifer, and no‐flux boundary representing an impermeable filter cake on the sides of the wall. The constant‐head and no‐flux boundary conditions yield significantly higher and lower shape factors, respectively, than those for the infinite aquifer. Consequently the conventional line‐fitting method for slug test analysis would yield an inaccurate estimate of the hydraulic conductivity of a vertical cutoff wall. 相似文献
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The line-fitting methods such as the Hvorslev method and the Bouwer and Rice method provide a rapid and simple means to analyze slug test data for estimating in situ hydraulic conductivity ( k ) of geologic materials. However, when analyzing a slug test in a relatively compressible geologic formation, these conventional methods may have difficulties fitting a straight line to the semilogarithmic plot of the test data. Data from relatively compressible geologic formations frequently show a concave-upward curvature because of the effect of the compressibility or specific storage ( S s ). To take into account the compressibility of geologic formations, a modified line-fitting method is introduced, which expands on Chirlin's (1989) approach to the case of a partially penetrating well with the basic-time-lag fitting method. A case study for a compressible till is made to verify the proposed method by comparing the results from the proposed methods with those obtained using a type-curve method (Kansas Geological Survey method [ Hyder et al. 1994 ]). 相似文献
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This paper examines the current procedure for determining the soil-water characteristic curve (SWCC) model with a particular focus on its application to slope stability analysis under transient unsaturated seepage conditions. A series of laboratory experiments was performed to determine the SWCC of different soils, ranging from high plasticity clay to silty sand, found across the Korean Peninsula. The experimental results were utilized to identify the suitable SWCC model for each soil type based on the fitting criterion. Also, this paper developed a numerical framework for infinite slope stability analysis under transient unsaturated seepage conditions. The significant advantage of the proposed framework, from the practical viewpoint, is to directly predict the timing of failure and potential failure plane based on rainfall recording. The effect of choice of SWCC models on predictability in stability analysis was evaluated by adopting the present framework along with the identified SWCC models. Furthermore, a case study of landslides after a 3-month rainfall in Pohang, Korea, was revisited to assess the performance of the proposed framework. The obtained results demonstrate the significant role of SWCC model on the results of slope stability analysis. The analysis using the SWCC model satisfying the fitting criterion could still not capture the real behavior of unsaturated soil. The comprehensive transient analysis is strongly suggested as a complementary means to the current fitting criterion for determining the suitable SWCC model for stability analysis under transient seepage conditions. 相似文献
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The groutability depends on the properties of the grout, its injection processes, and on the mechanical properties of the soil formation. During the process of pouring cement‐based grouting into a porous medium, a variation with time occurs in the viscosity of grout suspension. In addition, the particle filtration phenomenon will limit the expansion of the grouted zone because cement particles are progressively stagnant within the soil matrix. In this paper, a closed‐form solution was derived by implementing the mass balance equations and the generalized phenomenological filtration law, which can be used to evaluate the deposition of cement‐based grout in the soil matrix. The closed‐form solution relevant to a particular spherical flow was modified by a step‐wise numerical calculation, considering the variable viscosity caused by a chemical reaction, and the decrease in porosity resulting from grout particle deposition in the soil pores. A series of pilot‐scale chamber injection tests was performed to verify that the developed step‐wise numerical calculation is able to evaluate the injectable volume of grout and the deposition of grout particles. The results of the chamber injection tests concurred well with that of the step‐wise numerical calculation. Based on the filtration phenomenon, a viable approach for estimating the groutability of cement‐based grout in a porous medium was also suggested, which might facilitate a new insight in the design of the grouting process. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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The Bouwer and Rice method is a line-fitting method used to estimate the hydraulic conductivity of an aquifer by means of a slug test. When considering a relatively impermeable layer, called a filter cake, which may form at the interface between a cutoff wall and the natural soil formation, the assumptions of the Bouwer and Rice method are violated. A modification of the Bouwer and Rice method is proposed that incorporates the concept of a flow net, whereby the geometry of the cutoff wall and filter cake is effectively considered in estimating the hydraulic conductivity of a vertical cutoff wall. 相似文献
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