• Title, Summary, Keyword: Earth pressure

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Effect of the Earth Pressure Coefficient on the Support System in Jointed Rock Mass

  • Son, Moorak;Adedokun, Solomon;Hwang, Youngcheol
    • Journal of the Korean Geoenvironmental Society
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    • v.16 no.2
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    • pp.33-43
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    • 2015
  • This paper investigated the magnitude and distribution of earth pressure on the support system in jointed rock mass by considering different earth pressure coefficients, rock types and joint inclination angles. The study mainly focused on the effect of the earth pressure coefficients on the earth pressure. Based on a physical model test (Son & Park, 2014), extended studies were conducted considering rock-structure interactions based on the discrete element method, which can consider the joints characteristics of rock mass. The results showed that the earth pressure was highly influenced by the earth pressure coefficients as well as the rock type and joint inclination angles. The effects of the earth pressure coefficients increased when the rock suffered more weathering and has no joint slide. The test results were also compared with Peck's earth pressure for soil ground, and clearly showed that the earth pressure in jointed rock mass can be greatly different from that in soil ground. This study indicated the earth pressure coefficients considering the rock types and joint inclination angles are important parameters influencing the magnitude and distribution of earth pressure, which should be considered when designing the support systems in jointed rock mass.

The Lateral Earth Pressure on Braced Cut Walls Considering Subsoil Condition in Korea (국내 지반조건을 고려한 흙막이 백제에 작용하는 토압)

  • Chae, Young-Su;Moon, Il
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.129-138
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    • 1994
  • It is well recognized that accurate analysis of lateral earth pressure is very signficant factor which determines the design amount of braced cut walls and braced systems. Many researchers, Peck, Terzaghi-Peck and so on, make a study about lateral earth pressure to act on the flexible walls. But these studies trouble accurate to multy layered systems like inland areas in Korea. This study is compared with the field messurement data to estimate the earth pressure distributions in multy layered areas and the empirical earth pressure distributions. The conclusions are as follows : At final excavation depth, the lateral earth pressure which messured by field instrument is smaller than the empirical earth pressure. (About 1.85~5.32 times). In the case of considering the soft rock layer to the final excavation depth, the messured earth pressure is safe to be compared with empirical earth pressure. The messured earth pressure distributions are like that the upper soil layer is small the middle soil layer is large, the rock mass layer is very small.

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Estimation of Earth Pressures Acting on Box Structures Buried in Ground (지중에 매설된 박스구조물에 작용하는 토압 산정)

  • Hong, Won-Pyo;Yun, Jung-Mann;Song, Young-Suk
    • Journal of the Korean Geosynthetics Society
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    • v.14 no.2
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    • pp.23-33
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    • 2015
  • The earth pressure acting on underground structure was measured by application of the instrumentation system in the subway construction site constructed by the method of cut-and-cover tunnel. The measured earth pressure was compared with the earth pressure obtained from the existed theoretical equation, and the actual earth pressure diagram acting on the underground structure was investigated. As a result of investigation, the vertical earth pressure is mainly affected by the embankment height, and the lateral earth pressure is significantly affected by whether the existence of earth retaining structures or not. The measured vertical earth pressure is very similar to the theoretical earth pressure proposed by Bierbaumer. The measured lateral earth pressure is closed to the active earth pressure proposed by Rankine rather than the earth pressure at rest. The coefficient of earth pressure in soil deposit layer is about 0.35, and the coefficient in soft rock deposit layer is about 0.21. For design and construction the underground structures, therefore, it is reasonable estimation that the lateral earth pressure acting on structures installed in soil deposit layers is an average value between active earth pressure and earth pressure at rest. In rock deposit layers, the lateral earth pressure acting on structure is an active earth pressure only.

Static and seismic active lateral earth pressure coefficients for c-ϕ soils

  • Keshavarz, Amin;Pooresmaeil, Zahra
    • Geomechanics and Engineering
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    • v.10 no.5
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    • pp.657-676
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    • 2016
  • In this paper, the active lateral earth pressure is evaluated using the stress characteristics or slip line method. The lateral earth pressure is expressed as the lateral earth pressure coefficients due to the surcharge, the unit weight and cohesion of the backfill soil. Seismic horizontal and vertical pseudo-static coefficients are used to consider the seismic effects. The equilibrium equations along the characteristics lines are solved by the finite difference method. The slope of the ground surface, the wall angle and the adhesion and friction angle of the soil-wall interface are also considered in the analysis. A computer code is provided for the analysis. The code is capable of solving the characteristics network, determining active lateral earth pressure distribution and calculating active lateral earth pressure coefficients. Closed-form solutions are provided for the lateral earth pressure coefficients due to the surcharge and cohesion. The results of this study have a good agreement with other reported results. The effects of the geometry of the retaining wall, the soil and soil-wall interface parameters are evaluated. Non-dimensional graphs are presented for the active lateral earth pressure coefficients.

Earth pressure on a vertical shaft considering the arching effect in c-𝜙 soil

  • Lee, In-Mo;Kim, Do-Hoon;Kim, Kyoung-Yul;Lee, Seok-Won
    • Geomechanics and Engineering
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    • v.11 no.6
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    • pp.879-896
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    • 2016
  • A new earth pressure equation considering the arching effect in $c-{\phi}$ soils was proposed for the accurate calculation of earth pressure on circular vertical shafts. The arching effect and the subsequent load recovery phenomenon occurring due to multi-step excavation were quantitatively investigated through laboratory tests. The new earth pressure equation was verified by comparing the test results with the earth pressures predicted by new equation in various soil conditions. Resulting from testing by using multi-step excavation, the arching effect and load recovery were clearly observed. The test results in $c-{\phi}$ soil showed that even a small amount of cohesion can cause the earth pressure to decrease significantly. Therefore, predicting earth pressure without considering such cohesion can lead to overestimation of earth pressure. The test results in various ground conditions demonstrated that the newly proposed equation, which enables consideration of cohesion as appropriate, is the most reliable equation for predicting earth pressure in both ${\phi}$ soil and $c-{\phi}$ soil. The comparison of the theoretical equations with the field data measured on a real construction site also highlighted the best-fitness of the theoretical equation in predicting earth pressure.

An Experimental Study on Passive Earth Pressure of 3-Dimension (3차원 수동토압에 관한 실험적 연구)

  • 김기동;이상덕
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.489-496
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    • 1999
  • The safety of a structure can be improved by applying the three dimensional passive earth pressure. Because the three dimensional passive earth pressure is much larger than the two dimensional passive earth pressure and it is determined by the size(width B and height H) and the wall frictional angle of the resistant wall. Therefore, the three dimensional passive resistance behavior was studied through the model tests in sandy ground, where the size of the resistant wall and the wall frictional angle were varied. The results show that three dimensional passive earth pressure is 1.1∼3.4 times larger than that of the two dimensional value depending on the wall size and the wall friction.

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Effect of the Permeability of Excavation Wall on the Earth Pressure in a Jointed Rock Mass

  • Son, Moorak;Adedokun, Solomon
    • Journal of the Korean Geoenvironmental Society
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    • v.19 no.2
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    • pp.13-21
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    • 2018
  • The magnitude and distribution of earth pressure on the excavation wall in jointed rock mass were examined by considering different wall permeability conditions as well as rock types and joint inclination angles. The study was numerically extended based on a physical model test (Son & Park, 2014), considering rock-structure interactions with the discrete element method, which can consider various characteristics of rock joints. This study focused on the effect of the permeability condition of excavation wall on the earth pressure in jointed rock masses under a groundwater condition, which is important but has not been studied previously. The study results showed that the earth pressure was highly influenced by wall permeability as well as rock type and joint condition. Earth pressure resulted from the study was also compared with Peck's earth pressure in soil ground, and the comparison clearly showed that the earth pressure in jointed rock mass can be greatly different from that in soil ground.

A Simulation of Arching Earth Pressure Exerted on Vertical Shafts through Centrifuge Tests (원심모형실험에 의한 수직구 아칭토압 모사)

  • Lee, Dae-Soo;Kim, Kyoung-Yul;Hong, Sung-Yun;Kim, Yoo-Suk
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1073-1080
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    • 2010
  • In this paper, the centrifuge model tests were conducted for the sake of measuring three dimensional arching earth pressure while two step excavation of the vertical shaft. The results of the centrifuge model tests were compared to newly suggested arching earth pressure equation proposed by Kim et al(2009) and two dimension earth pressure(Rankine). As the results, Measured arching earth pressure revealed about 35 percentages of two dimension earth pressure(Rankine) and almost same as that of newly suggested arching earth pressure equation.

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An Experimental Study on the Earth Pressure Effect of Vertical Reinforcements (연직보강재의 토압경감 효과)

  • 문경선;이상덕
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.457-464
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    • 1999
  • The active earth pressure on the retaining wall is reduced by 3-Dimensional effects of the ground. Therefore, the test was focused on reducing the earth pressure on the retaining wall by inserting the vertical reinforcement in the backfill ground to develope the 3-Dimensional effects. Model tests in sand were peformed to measure the 3-Dimensional effects of the vertical reinforcement on the active earth pressure and its distribution and results were compared with the theories. The size of the vertical reinforcement, the geometry of the backfill space, and the wall friction of vertical reinforcement were varied. It was observed that the active earth pressure and its distribution on the underground structure were affected by the size of the vertical reforcements and wall friction.

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