scholarly journals Evaluation method of diversion length of capillary barrier composing of 3 layers ground in considering the thickness of the upper soil layer

2016 ◽  
Vol 11 (4) ◽  
pp. 305-313
Author(s):  
Kazunobu MATSUMOTO ◽  
Kaoru KOBAYASHI ◽  
Toshihiro MORII ◽  
Satoru NAKAFUSA
Keyword(s):  
Evaluation Method ◽  
Soil Layer ◽  
Capillary Barrier

scholarly journals Analysis and Evaluation Methods of Seismic Subsidence Characteristics of Loess and Field Seismic Subsidence

2021 ◽  
Vol 24 (4) ◽  
pp. 485-490
Author(s):  
Xiaotong Yan ◽  
Shun Wang ◽  
Ningwei Wang
Keyword(s):  
Evaluation Method ◽  
Soil Depth ◽  
Dynamic Properties ◽  
Soil Layer ◽  
Estimation Method ◽  
Dry Density ◽  
Cycle Times ◽  
Analysis And Evaluation ◽  
Stress Ratios ◽  
Triaxial Experiment

The objective of this research is to analyze the dynamic degeneration of loess and the evaluation method of field seismic subsidence. In this study, Q3 loess is taken as the research object, and the dynamic properties of loess with 10%, 20%, 30% and 35% moisture content are tested by triaxial experiment. In addition, seismic subsidence characteristics of loess with dry densities of 1.4g/cm3, 1.6g/cm3, and 1.8g/cm3 and consolidation stress ratios of 1.0, 1.2, 1.4, and 1.6 are analyzed. Then the simplified seismic subsidence estimation method is used to calculate the relationship between seismic subsidence coefficients at different soil depth in one dimensional field, cycle times, and subsidence depth. The results show that the higher the water content of loess is, the greater the change of seismic subsidence appears. The larger the dry density of loess is, the smaller the change degree of seismic subsidence appears. The larger the consolidation stress ratio is, the greater the change of seismic subsidence occurs in loess. When the depth of soil reaches 9.5m, the maximum seismic subsidence coefficient can reach 0.8%. When the depth of soil layer is 10m, the degree of seismic subsidence is the largest. When the depth of soil layer is 12~16m, the settlement depth caused by earthquake subsidence is small. While the depth of soil layer is 8~12m, the settlement degree is large.

NUMERICAL INVESTIGATION OF PERFORMANCE OF CAPILLARY BARRIER SYSTEM WITH TRANSPORT LAYER

2015 ◽  
Vol 77 (12) ◽  
Author(s):  
Gambo Haruna Yunusa ◽  
Azman Kassim ◽  
Zaihasra Abu Talib ◽  
Shabena Jasmin Mohamed Yoosoof
Keyword(s):  
Soil Layer ◽  
Climatic Conditions ◽  
Rainfall Infiltration ◽  
Transport Layer ◽  
Alternative Measure ◽  
Residual Soil ◽  
Capillary Barrier ◽  
Seepage Analysis ◽  
Promising Alternative ◽  
Rainfall Condition

A capillary barrier system is a promising alternative measure for controlling rainfall infiltration into unsaturated residual soil slopes. Although, system with capillary barrier effect has been successfully applied to avert rainfall infiltration in dry and semi-dry climates, its application in humid climates with high precipitation rate is still unsatisfactory. Therefore, this paper evaluates the performance of a modified capillary barrier system with transport layer under humid climatic conditions. The capillary barrier system and the transport layer were simulated with Grade V and Grade VI soils and gravel, respectively. The system was subjected to various rainfall intensities using saturated/unsaturated seepage analysis. When the initial suction of 32 kPa was assigned to the system and subjected to the worst rainfall condition for 24-hour duration, the breakthrough time increases with increase in the thickness of grade VI residual soil layer in the conventional capillary barrier system and the maximum diversion length achieved is less than 2 m. However, when a transport layer was placed at the interface of the grade V and grade VI soils, the diversion length increases to 15 m and avert breakthrough occurrence under the same condition. Therefore, the inclusion of transport layer in a residual soil capillary barrier system improved its performance and prevent breakthrough occurrence.

Comprehensive Evaluation on Testing Quality of Cement Mixing Pile of Weak Subgrade by Core Drilling Method

2014 ◽  
Vol 1065-1069 ◽  
pp. 1559-1563
Author(s):  
Yu Bin Hou ◽  
Yun Liu ◽  
Yan Jie Li
Keyword(s):  
Evaluation System ◽  
Quality Evaluation ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Soil Layer ◽  
Standard Test ◽  
Core Drilling ◽  
Drilling Method ◽  
Test Pile

Cement mixing pile is widely used in weak subgrade treatment and the quality of it has a direct bearing on the treatment effect of weak subgrade. Core drilling method is an effective method of testing quality of cement mixing pile. However, there are certain deficiencies in quality evaluation method of this kind of piles during practical application. In this paper, auxiliary evaluation criterion, established through standard test pile and combining with subgrade testing engineering is applied to the quality evaluation on test pile with construction deficiency after being combined with existing evaluation system. The result shows that the adoption of evaluation result of improved quality evaluation system can well reflect the pile construction quality of the test pile under complicated soil layer condition and is a reliable method of pile quality evaluation.

scholarly journals Evaluation of the Water Shielding Performance of a Capillary Barrier System through a Small-Scale Model Test

2021 ◽  
Vol 11 (11) ◽  
pp. 5231
Author(s):  
Byeong-Su Kim
Keyword(s):  
Model Test ◽  
Flow Condition ◽  
Large Scale ◽  
Soil Layer ◽  
Model Tests ◽  
Shielding Effect ◽  
Scale Model ◽  
Small Scale ◽  
Capillary Barrier ◽  
Large Scale Model

Capillary barrier (CB) systems consisting of a fine-grained soil layer placed over a coarse-grained soil layer can generally provide a water-shielding effect, increasing the slope stability of soil structures during rainfall. In order to improve the water-shielding performance of CB systems, laboratory model tests have been previously conducted under various conditions; notably, large-scale model tests are especially required. The inefficiency in increasing the production time of CB models until now explains their high cost. In this paper, we propose a laboratory small-scale CB (SSCB) model test for a quick and efficient evaluation of the function of a CB system. In this model test, differently from previous studies, a side drainage flow in the direction of the inclined sand layer was set as the no-flow condition; moreover, the laboratory SSCB model tests were performed by considering three rainfall intensities (i.e., 20, 50, and 100 mm/h) under the lateral no-flow condition. The results showed that the larger the rainfall intensity, the shorter the diversion length was of the CB system. To evaluate the effectiveness of the SSCB model test proposed in this study, the diversion length was estimated by an empirical equation under the lateral flow condition based on hydraulic conductivity functions and the soil water characteristic curves of sand and gravel and then compared to the results of the SSCB model tests. It was hence demonstrated that the water-shielding performance of the CB system can be efficiently evaluated through SSCB model tests under the lateral no-flow condition, rather than through large-scale model tests.

LABORATORY INVESTIGATION OF DRAINAGE CELL AS TRANSPORT LAYER IN RESIDUAL SOILS

2016 ◽  
Vol 78 (6-12) ◽  
Author(s):  
Gambo Haruna Yunusa ◽  
Azman Kassim
Keyword(s):  
Water Content ◽  
Slope Failure ◽  
Soil Layer ◽  
Transport Layer ◽  
Alternative Measure ◽  
Lower Grade ◽  
Residual Water ◽  
Capillary Barrier ◽  
Cell Transport ◽  
Set Up

Transport layer or unsaturated drainage layer is an alternative measure often employed to improve the performance of a capillary barrier system. A capillary barrier is an earthen cover used to prevent rainfall-induced slope failure. In this study, potential of using drainage cell system as transport layer is exploited using laboratory experimental methods. The drainage cell was sandwiched between grade V and grade VI soils in a two-dimensional laboratory slope model to act as transport layer. Coarse particles of gravel were compacted within the drainage cell to facilitate capillary break development at the interface. Each of grade V and grade VI soil was mixed with water content identical to residual water content determined from the soil water characteristic curves (SWCC) of each soil to enable simulation of their initial condition.  Both soils are then compacted in the slope model to their dry densities. The whole set up was subjected to three rainfall intensities of 1.0586 x 10-5 m/s, 1.2014 x 10-6 m/s and 3.7337 x 10-7 m/s for 2 hour, 24 hour and 7 day, respectively. These rainfall intensities were determined from Intensity-Duration-Frequency (IDF) curve and were applied through a rainfall simulator which is part of the laboratory set up. The results shows that the transport layer formed with drainage cell was capable of producing capillary break and impedes percolation of the infiltrating water into the lower grade V soil layer. The accumulated water was later drained laterally above the interface of grade VI soil and drainage cell transport layer towards the toe of the slope model. In an event that the infiltrating water percolates the drainage cell transport layer due to longer rainfall duration, the drainage cell provides a definite direction through which the infiltrating water flow and diverted laterally. It was found that the modified capillary barrier with drainage cell transport layer performed much better than the conventional capillary barrier system.

Construction And Test of An Instrumented 2D Channel With Rainfall And Insolation Control.

2021 ◽  
Author(s):  
Bruno Rogerio da Hora Lobo ◽  
Sandro Lemos Machado ◽  
Edson Pereira Marques Filho
Keyword(s):  
Clayey Soil ◽  
Soil Layer ◽  
Clayey Soils ◽  
Capillary Barrier ◽  
Shrinkage Cracks ◽  
Arid Conditions ◽  
One Year ◽  
Semi Arid ◽  
Coarse Soil

Abstract This paper presents the construction and testing of a large instrumented 2D channel for the simulation of the performance of compacted barriers under controlled conditions of insolation and rainfall. Details of the main apparatus devices and capabilities and the results of a long-term test performed on a capillary barrier (CB) are presented. The performed test aimed to simulate the CB behavior over a period of one year in typical semi-arid conditions. The channel behavior was considered very promising with its components functioning as expected and providing the desired information. Concerning the CB performance, it is shown that the upper clayey layer of soil presented undesirable shrinkage cracks that impacted the CB performance, mainly at the end of the period of evaluation. The obtained results point to the need to use of silty or low plasticity clayey soils in the CB design, despite the higher expected values of hydraulic conductivity, as well as the adoption of layers thicker than usual in order to preserve the integrity of the clayey soil near the interface with the bottom coarse soil layer.

Evaluation method for imaging plate resolution by means of phase contrast transfer function

1995 ◽  
Vol 53 ◽  
pp. 662-663 ◽  
Author(s):  
T. Oikawa ◽  
H. Kosugi ◽  
F. Hosokawa ◽  
D. Shindo ◽  
M. Kersker
Keyword(s):  
Transfer Function ◽  
Phase Contrast ◽  
Evaluation Method ◽  
Amorphous Film ◽  
Imaging Plate ◽  
X Rays ◽  
Special Shape ◽  
Contrast Transfer Function ◽  
Contrast Image ◽  
Specimen Shape

Evaluation of the resolution of the Imaging Plate (IP) has been attempted by some methods. An evaluation method for IP resolution, which is not influenced by hard X-rays at higher accelerating voltages, was proposed previously by the present authors. This method, however, requires truoblesome experimental preperations partly because specially synthesized hematite was used as a specimen, and partly because a special shape of the specimen was used as a standard image. In this paper, a convenient evaluation method which is not infuenced by the specimen shape and image direction, is newly proposed. In this method, phase contrast images of thin amorphous film are used.Several diffraction rings are obtained by the Fourier transformation of a phase contrast image of thin amorphous film, taken at a large under focus. The rings show the spatial-frequency spectrum corresponding to the phase contrast transfer function (PCTF). The envelope function is obtained by connecting the peak intensities of the rings. The evelope function is offten used for evaluation of the instrument, because the function shows the performance of the electron microscope (EM).

Combining Values

2002 ◽  
Vol 7 (2) ◽  
pp. 1-4, 12 ◽  
Author(s):  
Christopher R. Brigham
Keyword(s):  
Lower Extremity ◽  
Upper Extremity ◽  
Evaluation Method ◽  
Proximal Phalanx ◽  
Common Error ◽  
The Third ◽  
Whole Person ◽  
Impairment Ratings ◽  
Upper Extremity Impairment ◽  
The Individual

Abstract To account for the effects of multiple impairments, evaluating physicians must provide a summary value that combines multiple impairments so the whole person impairment is equal to or less than the sum of all the individual impairment values. A common error is to add values that should be combined and typically results in an inflated rating. The Combined Values Chart in the AMA Guides to the Evaluation of Permanent Impairment, Fifth Edition, includes instructions that guide physicians about combining impairment ratings. For example, impairment values within a region generally are combined and converted to a whole person permanent impairment before combination with the results from other regions (exceptions include certain impairments of the spine and extremities). When they combine three or more values, physicians should select and combine the two lowest values; this value is combined with the third value to yield the total value. Upper extremity impairment ratings are combined based on the principle that a second and each succeeding impairment applies not to the whole unit (eg, whole finger) but only to the part that remains (eg, proximal phalanx). Physicians who combine lower extremity impairments usually use only one evaluation method, but, if more than one method is used, the physician should use the Combined Values Chart.

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