암반지층 굴착벽체 작용토압에 대한 암반조건의 영향: 수치해석적 조사 Effect of Rock Mass Condition on the Earth Pressure Against an Excavation Wall in Rock Mass: Numerical Investigation원문보기
본 연구는 절리가 형성된 암반지층에서 암석종류, 절리경사각, 토압계수 및 지하수조건을 달리할 때 굴착벽체에 발생하는 토압의 크기 및 분포에 대해서 조사하였다. 모형실험(Son and Park, 2014)에 근거하여 확장연구를 수행하였으며, 이 때 암반-구조 상호작용과 암반의 절리특성을 고려하기 위하여 개별요소법을 이용한 수치해석을 수행하였다. 본 연구로부터 굴착벽체에 작용하는 토압은 암석종류, 절리경사각 및 토압계수 뿐만 아니라 지하수조건에 의해서 크게 영향을 받는다는 것을 파악하였다. 이와 더불어 본 연구로부터 조사된 토압을 토사지반에 적용되는 Peck의 경험토압과 비교하였으며, 이를 통해 절리형성 암반지층 굴착벽체에 발생하는 토압은 토사지반에서 발생하는 토압과 크게 다를 수 있다는 것을 확인하였다.
본 연구는 절리가 형성된 암반지층에서 암석종류, 절리경사각, 토압계수 및 지하수조건을 달리할 때 굴착벽체에 발생하는 토압의 크기 및 분포에 대해서 조사하였다. 모형실험(Son and Park, 2014)에 근거하여 확장연구를 수행하였으며, 이 때 암반-구조 상호작용과 암반의 절리특성을 고려하기 위하여 개별요소법을 이용한 수치해석을 수행하였다. 본 연구로부터 굴착벽체에 작용하는 토압은 암석종류, 절리경사각 및 토압계수 뿐만 아니라 지하수조건에 의해서 크게 영향을 받는다는 것을 파악하였다. 이와 더불어 본 연구로부터 조사된 토압을 토사지반에 적용되는 Peck의 경험토압과 비교하였으며, 이를 통해 절리형성 암반지층 굴착벽체에 발생하는 토압은 토사지반에서 발생하는 토압과 크게 다를 수 있다는 것을 확인하였다.
This study examined the magnitude and distribution of earth pressure on the excavation wall in jointed rock mass by considering different groundwater conditions under various rock types, joint inclination angles, and earth pressure coefficients. Based on a physical model test (Son and Park, 2014), e...
This study examined the magnitude and distribution of earth pressure on the excavation wall in jointed rock mass by considering different groundwater conditions under various rock types, joint inclination angles, and earth pressure coefficients. Based on a physical model test (Son and 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 groundwater condition as well as the rock type, joint inclination angle, and earth pressure coefficient. The 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 examined the magnitude and distribution of earth pressure on the excavation wall in jointed rock mass by considering different groundwater conditions under various rock types, joint inclination angles, and earth pressure coefficients. Based on a physical model test (Son and 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 groundwater condition as well as the rock type, joint inclination angle, and earth pressure coefficient. The 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.
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제안 방법
, 2015), focusing on the effect of groundwater condition under different rock type, joint inclination angle, and earth pressure coefficient. Extended numerical parametric studies were conducted by varying the groundwater condition together with the rock type, joint inclination angle, and earth pressure coefficient. The results from this study are expected to provide a better understanding of the earth pressure on the excavation wall in a jointed rock mass that can experience different rock mass coditions.
The joint inclination angle was measured in the anticlockwise direction from the horizontal plane, and the joint spacing was assumed to be 1 m. For each of the cases, the analysis was carried out using soldier pile and timber lagging wall. In order to reflect the general excavation procedures in the field, eight excavation stages were conducted to obtain the distribution and magnitude of earth pressure.
In order to reflect the general excavation procedures in the field, eight excavation stages were conducted to obtain the distribution and magnitude of earth pressure.
The numerical approach was extended to this parametric study, which considered the effect of different groundwater condition (no groundwater and groundwater with an impermeable wall) and earth pressure coefficient as well as rock types and joint inclination angles on the magnitude and distribution of earth pressure against the excavation wall in jointed rock masses.
This study extended the previous study (Son et al., 2015), focusing on the effect of groundwater condition under different rock type, joint inclination angle, and earth pressure coefficient. Extended numerical parametric studies were conducted by varying the groundwater condition together with the rock type, joint inclination angle, and earth pressure coefficient.
However, in a numerical analysis the shape may have a considerable influence on the results because of a stress concentration in modeling. To address this issue, this study transformed the excavation wall into a simple section to represent the equivalent flexural stiffness of the wall (see Fig. 6) using the method as shown below.
대상 데이터
The analysis model was 68.8 m × 31.5 m and the excavation wall was installed at the depth of 20.5 m (Fig. 4).
이론/모형
A fully coupled mechanical-hydraulic analysis was performed, in which joint porewater pressures affected the mechanical computations. The coupled behavior was examined using the method of fluid flow in joints provided by the DEM code.
To assess the characteristics of rock masses governed by joints, this study adopted 2-D Universal Distinct Element Code (UDEC, 2004), which allows for large displacements between blocks. The rock blocks, wall and struts were simulated as separate elastic elements.
성능/효과
(2) As the rock and joint conditions were weathered more, the induced earth pressure increased, the effect of groundwater decreased, the effects of earth pressure coefficient increased, and the effects of joint inclination angles decreased.
(3) When joint sliding was induced, the sliding effect was more significant in hard rock and the effect was relatively small in moderately weathered rock. In moderately weathered rock, the high deformability of the rock and joint decreased the effect of joint inclination angle and groundwater.
(4) When the joint inclination angle was 30° in hard rock and good joint conditions, the induced earth pressure under groundwater condition increased significantly with the increase of earth pressure coefficient, but the effect of earth pressure coefficient on the induced earth pressure was very small when joint sliding was induced.
The results clearly showed that the earth pressure can be higher for rock strata than soil ground when the rock and joint characteristics are under unfavorable conditions, such as a joint condition that induces sliding and a weathered joint and rock condition.
For a joint inclination angle of 30°, the induced earth pressures for all the earth pressure coefficients were significantly higher than those of hard and slightly weathered rocks due to the higher tendency of block displacement in moderately weathered rock. The results showed that earth pressures increased constantly with the increase of the earth pressure coefficient and the increase rate was much higher than that in slightly weathered rock. The effects of groundwater on the earth pressure were much lower than those of hard and slightly weathered rocks and there was no groundwater effect at the high earth pressure coefficients of 2.
후속연구
Extended numerical parametric studies were conducted by varying the groundwater condition together with the rock type, joint inclination angle, and earth pressure coefficient. The results from this study are expected to provide a better understanding of the earth pressure on the excavation wall in a jointed rock mass that can experience different rock mass coditions.
참고문헌 (11)
Chae, Y. S. and Moon, I. (1994), "Earth Pressure on Retaining Wall by Considering Local Soil Condition", Korean Geotechnical Society, '94 Fall conference paper, pp.129-138.
Jeong, E. T. and Kim, S. G. (1997), "Case Study of Earth Pressure Distribution on Excavation Wall of Multi-layered Soil", Korean Geotechnical Society, '97 spring conference paper, pp. 78-80.
Peck, R.B. (1969), "Deep Excavations and Tunneling in Soft Ground. State-of-the-Art report", Proceedings of the 7th International Conference on Soil Mechanics and Foundation Engineering, Mexico City, State-of-the Art Volume, pp.225-290.
Son, M. (2013), "Earth Pressure on the Support System in Jointed Rock Mass", Canadian Geotech. Journal, Vol.50, No.5, pp.493-502.
Son, M. and Adedokun, S. (2015), "Effect of Support Characteristics on the Earth Pressure in a Jointed Rock Mass", Canadian Geotech. Journal, Vol.52, pp.1-12.
Son, M., Adedokun, S., and Hwang, Y. (2015), "Effect of the Earth Pressure Coefficient on the Support System in Jointed Rock Mass", Journal of the Korean-Geoenvironmental Society, Vol. 16, No.2, pp.33-43.
Son, M. and Park, J. (2014), "Physical Model Test and Numerical Simulation of Excavation Wall in Jointed Rock Mass", Canadian Geotech. Journal, Vol.51, No.5, pp.554-569.
Son, M. and Yoon, C. (2011), "Characteristics of the Earth Pressure Magnitude and Distribution in a Jointed Rockmass", Journal of Korean Society of Civil Engineers, Vol.31, No.6, pp.203-212.
Tschebotarioff, G. P. (1973), Foundations, Retaining and Earth Structures. 2nd Ed., MGH.
Yoo, C. S. and Kim, Y. J. (2000), "Deep Excavation in Soil, Including Rock with Layers on Retaining Wall and Apparent Horizontal Displacement of Earth Pressure", Journal of Korean Geotechnical Society, Vol.16, No.4, pp.43-50.
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