Earth Pressure on an Excavation Wall in Rock Mass

Solomon Adedokun,손무락 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.10

In this study, the earth pressure on an excavation wall in rock mass is investigated under various conditions (type of rock, angle of join inclination, shear strength of joint, groundwater, permeability of wall, and earth pressure coefficient at rest). Based on the results of a physical model test of an excavation wall in joined rock mass, extended parametric study is performed considering the rock-structure interaction based on the discrete element method. The study results suggest that the earth pressure is strongly influenced by the condition of groundwater as well as the condition of wall and rock mass. The effect of groundwater on the earth pressure in a jointed rock mass different depending on rock type, the earth pressure coefficient at rest, wall permeability, and joint inclination angle. The groundwater effect was greatest under an impermeable wall condition and a vertical joint acted as an impermeable wall. Under inclined joint and groundwater conditions, the earth pressure in a permeable wall increased when compared with no groundwater condition and the increase was more evident when the earth pressure coefficient was smaller. As the rock and joint conditions were deteriorated further, the earth pressure increased and the influence of groundwater decreased. The study results also showed that for hard rock and good joint conditions, the influence of groundwater was more significant as the earth pressure coefficient increased, but as rock and joint weathered, the influence of groundwater was more significant as the earth pressure coefficient decreased.

Earth Pressure on a Retaining Structure in Layered and Jointed Rock Masses

손무락,Solomon Adedokun 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.4

This work looked into the earth pressure induced on retaining walls in different rock layer formations and joint conditions. Based on the simulation of a large-scale expermental test, extended numerical tests were carried out focusing on the effect of various rock layer formations on earth pressure characteristics. The earth pressures induced from single and multi-layered rocks were compared in terms of magnitude and distribution. The comparison showed that a rock layer formation affects the earth pressure on a retaining structure considerably depending on the composition of rock layer with regard to rock type and thickness. Additionally, the analysis results were compared with Peck’s soil earth pressure and it was turned out that a layered and jointed rock mass induces the earth pressure considerably different from those both in a single-layer rock mass and in soil ground. The findings form this work can help understand the characteristics of the earth pressure caused by excavation activities in layered and jointed rock masses.

Effect of Joint Inclination Angles on the Earth Pressure Against the Support System in a Jointed Rock Mass

손무락,Solomon Adedokun 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.4

This study investigated the magnitude and distribution of the earth pressure on the support system in a jointed rock mass, due to the different joint inclination angles, joint shear conditions, and rock types. The study mainly focused on the sensitivity of the joint inclination angles on the earth pressure. Based on a physical model test (Son and Park, 2014), extended numerical parametric studies were conducted considering rock-structure interactions based on the discrete element method, which can consider the rock and joint characteristics of rock mass. The results of numerical tests were compared with an analytical method based on a wedge theory. The comparison showed that the earth pressure was highly influenced by the joint inclination angles, together with different rock types. The study indicated that the effect of joint inclination angle was particularly more significant when a rock type was harder and a joint was under the condition of joint sliding. The test results were also compared with Peck’s earth pressure, which has been frequently used for soil ground. The comparison showed that the earth pressure in a jointed rock mass can be significantly different from that in soil ground depending on the joint inclination angles and rock types.

Earth Pressure Envelope for Retaining Wall in Jointed Rock Ground

손무락,Solomon I. Adedokun 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.12

Earth pressure against a retaining wall in a jointed rock ground are an important factor for design and construction. A physical model test, extensive numerical studies, and field observations were conducted and comprehensively analyzed. All of the results were integrated and analyzed to develop an earth pressure envelope for the design of retaining walls in a jointed rock ground. For this purpose, the rock mass conditions and induced earth pressures were systematically investigated for different analysis cases. The rock mass conditions were classified using the slope mass rating (SMR) method and divided into six rock mass classes. The induced earth pressures of cases in the same rock mass class were plotted together, and an earth pressure envelope that covers the induced earth pressures in each rock mass class was developed. The developed envelope was compared with field observations, which show that the field results are generally consistent with the developed envelope in the same rock mass class. The study results and developed earth pressure envelope could help to provide a better understanding and design of retaining walls in a jointed rock ground.

Comparison of Earth Pressure between Numerical and Analytical Methods for Jointed Rock Wedges

손무락,Solomon Adedokun 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.7

The magnitude of earth pressure of jointed rock wedges against a support system was investigated both analytically and numerically. Analytical method was based on the wedge analysis and numerical method was based on the discrete element method. To consider various rock wedge conditions, the controlled parameters included the rock type, number of joint, and joint shear condition. The results of analytical method were compared with the numerical test results. The comparison showed that the earth pressure of jointed rock wedges can be assessed larger by the analytical method than the numerical method and as the number of joints increases, the results of both methods becomes closer. In addition, the results indicated that the earth pressure of jointed rock wedges was strongly dependent on the rock type, number of joint, and joint shear condition. This study suggested that both the ground-structure interaction and rock and joint conditions are important for assessing the earth pressure of jointed rock wedges, and these factors should be considered when designing a support system economically and reasonably against jointed rock wedges.

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

Son, Moorak,Adedokun, Solomon Korean Geo-Environmental Society 2018 한국지반환경공학회논문집 Vol.19 No.2

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.

Effect of Joint Spacing on the Earth Pressure Against the Support System in a Jointed Rock Mass

Son, Moorak,Adedokun, Solomon Korean Geo-Environmental Society 2016 한국지반환경공학회논문집 Vol.17 No.1

This study examined the magnitude and distribution of earth pressure on the support system in a jointed rock mass due to the different joint spacing as well as varying the rock type and joint condition (joint shear strength and joint inclination angle). Based on a physical model test and its numerical simulation, a series of numerical parametric analyses were conducted using a discrete element method. The results showed that the magnitude and distribution of earth pressure were strongly affected by the different joint spacing as well as the rock type and joint condition. In addition, the study results were compared with Peck's earth pressure for soil ground, which indicated that the earth pressure in a jointed rock mass could be considerably different from that in soil ground. The study suggests that the joint spacing as well as the rock type and joint condition are important factors affecting the earth pressure in a jointed rock mass and they should be considered when designing a support system in a jointed rock mass.

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

Moorak Son,Solomon Adedokun 한국지반환경공학회 2018 한국지반환경공학회논문집 Vol.19 No.2

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.

Effect of Joint Spacing on the Earth Pressure Against the Support System in a Jointed Rock Mass

Moorak Son,Solomon Adedokun 한국지반환경공학회 2016 한국지반환경공학회논문집 Vol.17 No.1

This study examined the magnitude and distribution of earth pressure on the support system in a jointed rock mass due to the different joint spacing as well as varying the rock type and joint condition (joint shear strength and joint inclination angle). Based on a physical model test and its numerical simulation, a series of numerical parametric analyses were conducted using a discrete element method. The results showed that the magnitude and distribution of earth pressure were strongly affected by the different joint spacing as well as the rock type and joint condition. In addition, the study results were compared with Peck’s earth pressure for soil ground, which indicated that the earth pressure in a jointed rock mass could be considerably different from that in soil ground. The study suggests that the joint spacing as well as the rock type and joint condition are important factors affecting the earth pressure in a jointed rock mass and they should be considered when designing a support system in a jointed rock mass.

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

Moorak Son,Solomon Adedokun,Youngcheol Hwang 한국지반환경공학회 2015 한국지반환경공학회논문집 Vol.16 No.2

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.