• Title/Summary/Keyword: weathered degree

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Shear Characteristics of Weathered Granite Soils for Degree of Weathering and Saturation (화강토의 풍화도와 포화도에 따른 전단특성)

  • Song, Chang-Seob;Jang, Wong-Hee
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.3 no.3
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    • pp.1-7
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    • 2000
  • The aim of the work described in this paper is to study the shear characteristics of the weathered granite soil. To this end, a series of consolidated undrained triaxial compression tests are carried out to investigate the shear parameters-cohesion and internal friction angle for the degree of saturation and degree of weathering. From the results, it is found that the shear parameters of weathered granite soil are influenced on the degree of saturation, degree of weathering and disturbance. Especially, internal friction angle is more influenced on the upper factors than cohesion. And shear parameters are more acted on the degree of saturation than the degree of weathering in the test range. It is, therefore, recommended that must be considered the conditions of granite soil-degree of saturation, degree of weathering and disturbance etc-in case of the calculation of bearing capacity, stability analysis and other designs with shear parameters.

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A Study on the Strength Degradation of Weathered Granite Soil by Freezing and Thawing (동결융해에 의한 화강풍화토의 강도저하에 관한 연구)

  • Kim, Yong-Soo;Jung, Soo-Jung
    • Journal of the Korean Geosynthetics Society
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    • v.6 no.3
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    • pp.1-7
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    • 2007
  • The property of weathered soil cannot but have a possibility of having a limit when its precise approaching due to the various weathering environment, and the peculiarity of its conduct affected by the weathering degree and effect factors. Especially most domestic or international researches are concentrated on the sedimentary soil, trying to analyze the mechanical behavior of weathered soil from the viewpoint of sedimentary soil. Therefore, it's difficult to judge if those results meet the actual conduct of weathered soil. This study suggested a way of weathering degree changing experiment as an early stage in an experiment of artificially changing weathering degree. In order to find out the property of strength change by the change of weathering degree, indoor mechanical experiment was made using soil sample after freezing and thawing. Under the weathering degree, characteristic change is watched by country rock and region of weathered granite soil.

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Bearing Capacity and Settlement Characteristics of Weathered Granite Masses in Gyeonggi Area (경기지역 화강 풍화암반의 지지력 및 침하특성에 관한 연구)

  • Kim, Dong-Eun;Huh, Kyung-Han
    • Journal of the Korean Society of Hazard Mitigation
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    • v.5 no.4 s.19
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    • pp.37-47
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    • 2005
  • The purpose of this study is to estimate the bearing capacity and settlement characteristics of the weathered granite masses, and on the process to achieve the purpose, in the first place, the weathered degree according to the absorption index was examined and reviewed, then plate bearings test in in-situ depth were tested, and finally the result was compared and examined with the result of the existing, estimate method and pressuremeter test. In order to achieve the purpose of this study, a typical area distributed with weathered granite masses, gyeonggi area, was chosen as a sample site for testing, and in the result, it appeared and found out that the more the weathered degree increases when the plate bearing test are tested, the more the bearing capacity decreases a numerical indexes and the more greatly the width of the decrease of bearing capacity increases around the boundary of specific, weathered degrees. Also, In the result from estimating the bearing capacity of weathered granite masses by the existing, suggested formula, it appeared that there is a tendency that the more the weathered degree increases, the more similar the bearing capacity becomes with the result of plate bearing tests.

Estimation of Weathered Degree Using Fall cone in Weathered Soil ; Silty Sand (Fall Cone을 이용한 풍화도 측정(실트질 모래에 대하여))

  • Son, Young-Hwan;Kim, Seong-Pil;Chang, Pyoung-Wuck
    • Journal of The Korean Society of Agricultural Engineers
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    • v.50 no.1
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    • pp.61-68
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    • 2008
  • It is essential to analyze and classify the physical characteristics of weathered granite for engineering purposes. This paper is to suggest a physical method to determine the degree of weathering of weathered soils. A new classification method for determining the degree of weathering is suggested, based upon the results from laboratory tests including fall cone test. According to the proposed physical method using fall cone apparatus, the measured values of the samples from the same area show distinctive difference of weathering. The water content tends to increase with increasing the degree of weathering at the same penetration in fall cone test. And relationship between CWI and water content are expressed one equation in Hwaseong area and Ilsan area.

Estimating the Soil Volume Conversion Factor of Weathered Ground with Consideration of Field Situations

  • Jin, Kyu-Nam;Cho, Gye-Chun;Lee, Jung-Min;Ryu, Hee-Hwan;Park, Sung-Wook
    • Land and Housing Review
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    • v.2 no.2
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    • pp.145-155
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    • 2011
  • It is very important for successful construction to estimate the soil volume conversion factor of domestic weathered ground accurately and reasonably. However, it is very difficult to quantify the weathering degree of weathered ground at the field, so that the soil volume conversion factor used in Korea is often dependent upon the standard of foreign countries. Besides, the soil volume conversion factor of domestic weathered ground has been rarely studied and the use and accuracy of the soil volume conversion factor have been questioned persistingly. This study suggests a simple but robust method for estimating the soil volume conversion factor and measuring the weathering degree reasonably, and attempts to establish the utilization of a soil volume conversion factor measurement system based on experimental and analytical results. We made relationship between electrical resistivity and weathering degree presented from weathering index obtained through laboratory tests using field samples, and an estimation method of in-situ weathering degree for granites and a calculation method of soil volume conversion factor using electrical resistivity. And also, we suggested the photogrametry measurement-equipment system for measuring the volume of cargo box and the application plan of stand equipment and RFID for calculating the earth volume and distinguishing buggies in order to design the measurement system for soil volume conversion factor applicable to the field. Ultimately, the Weathered Earth-work Management Program (WEMP) was developed, so field managers may easily obtain the information about earth volume and soil volume conversion factor at the weathered ground.

Mechanical Characteristics of Weathered Granite Soils for Degree of Weathering and Saturation (풍화도과 포화도에 따른 화강토의 역학적 특성)

  • Lim, Seongyoon;Song, Changseob;Kim, Myeonghwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.57 no.3
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    • pp.93-100
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    • 2015
  • The object of this paper is to study the shear characteristics of the weathered granite soil. To this end, a series of consolidated undrained triaxial compression tests are carried out to investigate the shear parameters-cohesion and internal friction angle-for the degree of saturation and degree of weathering. From the results, it is found that the shear parameters of weathered granite soil are influenced on the degree of saturation, degree of weathering and disturbance. Especially, internal friction angle is more influenced on the upper factors than cohesion. And shear parameters are more acted on the degree of saturation than the degree of weathering in the test range. It is, therefore, recommended that must be considered the conditions of granite soil-degree of saturation, degree of weathering and disturbance etc-in case of the calculation of bearing capacity, stability analysis and other designs with shear parameters.

Investigation into Weathering Degree and Shear Wave Velocity for Decomposed Granite in Hongsung (홍성 지역 화강 풍화 지층에 대한 풍화도 및 전단파 속도 고찰)

  • Sun, Chang-Guk;Kim, Bo-Hyun;Chung, Choong-Ki
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.360-372
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    • 2005
  • The weathering degree and shear wave velocity, $V_S$, were evaluated for decomposed granite layers in Hongsung, where earthquake damages have occurred. The subsurface geological layers and their $V_S$ profiles were determined, respectively, from boring investigations and seismic tests such as crosshole, downhole and SASW tests. The subsurface layers were composed of 10 to 40 m thickness of weathered residual soil and weathered rock in most sites. In the laboratory, the weathering indexes with depth were estimated based on the results of X-ray fluorescence analysis using samples obtained from field, together with the dynamic soil properties determined from resonant column tests using reconstituted specimens. According to the results, it was examined that most weathering degrees represented such as VR, Li, CIA, MWPI and WIP were decreased with increasing depth with exception of RR and CWI. For weathered residual soils in Hongsung, the $V_S's$ determined from borehole seismic tests were slightly increased with increasing depth, and were similar to those from resonant column tests. Furthermore, the $V_S$ values were independent on the weathering degrees, which were decreased with depth.

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A Study of Engineering Properties and Deformation Behavior of Weathered Rock Mass (풍화 암반의 공학적 특성 및 변형거동에 관한 연구)

  • 강추원;박현식;김수로
    • Explosives and Blasting
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    • v.22 no.2
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    • pp.33-43
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    • 2004
  • The six grades weathering system is normally used in weathered rock classification. In this study. fresh and weathered rock block of grade I to V were sampled in Jang-soo ana but samples of the grade VI was omitted from this study. The variation quantities of chemical weathering indices with weathering degree are smaller than those of physical and mechanical properties. Increase of Weathering degree is well indicated by physical and mechanical properties such as strength, hardness, ultrasonic velocity and slake durability result. Especially, absorption and porosity ratio is a good indicator. As weathering proceeds. a number of the cracks affect the rock deformation. Therefore, stress-strain curves of weathered rocks in unconfined state are quite different from ones of fresh rocks.

Evaluation on Ground Characteristics of Weathered Granite Masses by Pressuremeter Test (공내재하시험에 의한 화강 풍화암의 지반 특성 평가)

  • Lee, Kwang-Hee;Bae, Kyung-Tae;Chang, Seo-Man;Lee, Chong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.831-838
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    • 2004
  • To study on mechanical characteristics of weathered granite masses are difficult because of undisturbanced sampling and in-situ test. Generally, pressuremeter test is widely used to investigate the behavior of weathered rock masses. However, it has many problems to get a limit pressure because of cavity collapse, membrane damage, ete. This study aims to evaluate the mechanical characteristics of weathered granite masses using in-situ pressuremeter test and numerical analysis depending on the ratio of length and diameter of the membrane(L/D=5, 8, 10, 15, 20). Test results and data are shown that strength parameters are reduced exponentially varing weathering degree, and numerical analysis results are approximately coincided with the test results. And the ratio of length and diameter of the membrane arc not affected the parameters such as modulus of pressuremeter, shear modulus, etc. But limit pressure is increased decreasing membrane length based on numerical analysis. On the other hand, increasing the membrane length, yield pressure is decreased and plastic radius is increased in the case of same weathering degree.

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A Case Study on Geotechnical Properties and Weathering Degree of Weathered Granite Rock (화강 풍화암의 지반특성 및 풍화도 평가에 대한 사례 연구)

  • Lee, Seung-Hwan;Yoo, Byeong Soo;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.33 no.12
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    • pp.127-139
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    • 2017
  • Site investigation including boring and various in-situ borehole test (Pressuremeter test, Borehole shear test, Downhole test, Suspension PS logging, Density logging) and X-ray fluorescence analysis for rock core sample were performed to estimate geotechnical properties and weathering degree of weathered granite rock in Goyang. Deformation modulus, shear strength parameter and shear wave velocity estimated through in-situ borehole test had a tendency to increase with depth. And several chemical weathering indices evaluated by X-ray fluorescence analysis had a general tendency of reducing weathering degree in accordance with depth. Also, relationship between VR determined as a representative weathering index and the geotechnical properties was analyzed.