• Geomechanics and Engineering
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• v.35 no.5
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• pp.555-570
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• 2023

In the current study, a series of experimental and analytical evaluations were performed to introduce the horizontal pseudo static coefficient (kh) as a function of the wall configuration and the reinforcement type for analyzing reinforced soil walls. For this purpose, eight shaking table tests were performed on reduced-scale models of integrated and two-tiered walls reinforced by metal strip and geogrid to determine the distribution of dynamic lateral pressure in the walls. Then, the physical models were analyzed using Mononobe-Okabe method to estimate the value of kh required to establish the dynamic lateral pressures similar to those observed in shaking table tests. Based on the results, the horizontal pseudo static coefficient and the position of resultant lateral force (R) were introduced as a function of the horizontal peak ground acceleration (HPGA), the wall configuration, the reinforcement type as well as maximum wall displacement.

• Earthquakes and Structures
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• v.15 no.3
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• pp.243-251
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• 2018

The dynamic responses of a rocking wall-moment frame (RWMF) with a post-tensioned cable are investigated. The nonlinear equations of motions are developed, which can be categorized as a single-degree-of-freedom (SDOF) model. The model is validated through comparison of the rocking response of the rigid rocking wall (RRW) and displacement of the moment frame (MF) against that obtained from Finite Element analysis when subjected ground motion excitation. A comprehensive parametric analysis is carried out to determine the seismic performance factors of the RWMF systems under near-fault trigonometric pulse excitation. The horizontal displacement of the RWMF system is compared with that of MF structures without RRW, revealing the damping effect of the RRW. Frame displacement spectra excited by trigonometric pulses and recorded earthquake ground motions are constructed. The effects of pulse type, mass ratio, frame stiffness, and wall slenderness variations on the displacement spectra are presented. The paper shows that the coupling with a RRW has mixed results on suppressing the maximum displacement response of the frame.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.593-608
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• 2018

If a problem occurs in the strut during the construction of the braced wall, they may cause excessive deformation of the braced wall. Therefore, in this study, the behavior of the braced wall and existing tunnel adjacent to excavation were investigated assuming that the support function of strut is lost during construction process. For this purpose, a series of model test was performed. As a result of the study, the earth pressure in the ground behind wall was rearranged due to the deformation of the braced wall, and the ground displacements caused the deformation of adjacent tunnels. When the struts located on the nearest side wall from the tunnel were removed, the deformation of the braced wall and the tunnel deformation were the largest. The magnitude of transferred earth pressure depended on the location of tunnel. The increase of the cover depth of tunnel from 0.65D to 2.65D caused the increase of the earth pressure by 25.6%. As the distance between braced wall and tunnel was increased from 0.5D to 1.0D, the transferred earth pressure increased by 16% on average. Horizontal displacements of braced wall by the removal of the strut tended to concentrate around the removed struts, and the horizontal displacement increased as the strut removal position is lowered. The tunnel displacement was maximum, when the cover depth of tunnel was 1.15D and the horizontal distance between braced wall and the side of tunnel was 0.5D. The minimal displacement occurred, when the cover depth of tunnel was 2.65D and the horizontal distance between braced wall and the side of tunnel was 1.0D. The difference between the maximum displacement and the minimum displacement was about 2 times, and the displacement was considered to be the largest when it was in the range of 1.15D to 1.65D and the horizontal distance of 0.5D.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.49-57
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• 2005

The purpose of this study is to closely examine the influence of the surcharge load applied to the retaining wall through some model tests, in which wall stiffness in each stage of excavation, horizontal displacement of the retaining wall and surface displacement of the backfill according to wall stiffness and ground conditions, and change and distribution of the earth pressure applied to it were measured and their values were produced, then these values were mutually compared with their theoretical values and their values after analysis of the data obtained at the field, and they were analytically studied, in order to closely examine the influence of the surcharge load applied to the retaining wall. Findings from this study are as follows: The shape of ground surface settlement curve on the model ground under surcharge load, different from the distribution curve of regular probabilities which is of a shape of ground surface settlement under no surcharge load, appears in that settlement in an arching shape shows where the center part of surcharge load shows the maximum settlement. In examining the maximum horizontal displacement with the surcharge load applied to each stage of excavation, it occured at the point of 0.8H(excavation depth) when finally excavated. Regarding the range in which the displacement of the retaining wall increases according to application of surcharge load, the increment of displacement showed till the point of depth which is of two times of the distance of load from the upper part of the wall. Also since each displacement of the foundation plate caused by the ground surface settlement according to each stage of excavation occured most significantly at the final stage. Also since regarding wall stiffness, the wall of its thickness of 4mm(flexible coefficient $p:480m^3/t$), produced maximum 3 times of wall stiffness than its thickness of 9mm(flexible coefficient $p: 40m^3/t$), it was found out that influence of wall stiffness is so significant.

• Tunnel and Underground Space
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• v.17 no.5
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• pp.350-359
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• 2007

Most large cut slopes of open pit mines, roadways, and railways are steeply inclined and composed with rocks that do not contain soils. However, these rock slopes suffer both weathering and fragmentation. In the case of steep slopes, falling rock and collapse of a slope may often occur due to surface erosion. Cast-in place concrete and rubble work are the most widely used earth structure-based pressure supports that act as restraints against the collapse of the rock slope. In order to overcome the shortcomings of conventional retaining walls, a segmental grid retaining wall is being used with connects precasted segments to construct the wall. In this study, laboratory model test was conducted to estimate deformation behavior of segmental grid retaining wall with configuration of rear strecher, height and inclination of the wall. In order to examine the behavior characteristics of a segmental grid retaining wall, this research analyzes the aspects of spacial displacement through relative displacement according to change in the inclination of the wall. Also, the walls behavior according to the formation and status of the rear stretcher which serves the role of transferring the load from the header and the stretcher which make up the wall, the displacement of backfill materials in the wall, and the location of the maximum load were surveyed and the characteristics of displacement in the segmental grid retaining wall were observed. The test results of the segmental grid retaining wall showed that there was a sudden increase in failure load according to the decrease in the wall's height and the size of the in was greatly decreased. Furthermore, it revealed that with identical inclination and height, the structure of the rear stitcher did not greatly affect the starting point or size of maximum horizontal displacement, but rather had a stronger effect on the inclination of the wall.

• Journal of the Korean GEO-environmental Society
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• v.7 no.4
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• pp.15-24
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• 2006

It is well known that earth pressure on the cylindrical open caisson and cylindrical retaining wall of a shaft is less than that at-rest and in plane strain condition because of the horizontal and vertical arching effects due to wall displacement and stress relief. In order to examine the earth pressure distribution of a cylindrical wall, model tests were performed in dry sand for the care of constant wall displacement with depth. Model test apparatus which can control wall displacement, wall friction, and wall shape ratio was developed. The effects of various factors that influence earth pressure acting on the cylindrical retaining wall of a shaft were investigated.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.179-188
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• 2018

A new style of panel-type reinforced earth wall is a more integrated structure by connecting the geosynthetic strip reinforcement with a folding groove directly to the front panel through C-shaped insertion hole embedded in the panel. In this study, field measurements were conducted on two reinforced earth walls constructed at different sites to assess the field applicability and structural stability of the new style of panel-type reinforced earth wall. The horizontal displacement of the front panel, tensile deformation of the geosynthetic strip reinforcement, and horizontal earth pressure acting on the panel were measured and analyzed through the field measurements. According to the field measurements, after completion of the reinforced earth wall construction, the maximum horizontal earth pressure applied to the front panel was less than two-thirds of the Rankine earth pressure, and the maximum horizontal displacement of the front panel was less than 0.5% of the wall height, and the maximum tensile strain generated on the reinforcement was less than 1.0%. Therefore, it was found that two reinforced earth walls constructed at different sites remained stable.

• Structural Engineering and Mechanics
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• v.14 no.3
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• pp.365-380
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• 2002

Following a series of experiments on isolated low-rise RC shear walls with openings, a theoretical study on the backbone curve of a perforated shear wall shows that there are some important observations from experimental results that make clear a semi-empirical formula of the backbone curve of a perforated wall. Critical shear zones can be depicted from the configuration of shear walls with openings. Different factors, including the size and location of shear wall openings, the wall's height/width ratio, horizontal and vertical steel bar ratios, and location and amount of diagonal steel bars are involved in the derivation of the backbone curve. Bending and shear effects are also considered in the paper. In addition, a comparison of load and displacement for solid and perforated shear walls is discussed. Generally, the comparison between experimental curves and computed backbone curves is favorable.

• Geomechanics and Engineering
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• v.36 no.6
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• pp.527-543
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• 2024

In the implementation of most civil structures, especially underground, deep excavations with a vertical slope are required. Using flexible retaining walls is applied as one of the ways to stabilize vertical holes. Therefore, it is necessary to know the parameters affecting the performance of such walls in reducing their horizontal movement. In this research, by building a suitable laboratory model, the parameters of the amount of flexibility, the embedment depth of the wall, the type and number of tieback in the wall were investigated for 42 static laboratory models. The purpose of this research is to study the flexible retaining wall with helical tieback compared to simple tieback at different heights, which shows the best performance in terms of reducing horizontal displacement in proportion to increasing or decreasing flexibility. On the other hand, one of the parameters affecting the flexibility of the wall, which is its bending stiffness, was extracted by numerical software outputs and studied on the results such as relative flexibility, stiffness, safety and numerical stability of the wall.The results of this study show that among the parameters, in the first place, the effect of the type of tieback is inhibited and in the second place, the ratio of thickness to wall height is known as the most important parameter. the best performance for walls with the helical tiebacks in reducing their horizontal displacement can be economically, flexibly and stability assigned to a wall that tiebacks is in the range of H2/t to H4/t and its flexibility ratio is 2/3.

• Journal of the Korean Geosynthetics Society
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• v.18 no.2
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• pp.23-36
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• 2019

In this paper, field measurement of the Block Type Mechanically Stabilized Earth (MSE) wall curved section was performed, and the reinforced area of the curved part is studied through the result. MSE method has been applied to various fields because of easy construction and excellent economic efficiency, so that it can be easily access in our life. However due to lack of compaction and stress concentration phenomenon, cracks and collapse occur in the curve of MSE wall, which is important for safety. The cause of collapse is lack of research on curved section, lack of design criteria, lack of construction due to economical efficiency and shortening of construction period, insufficient compaction space. In this study, therefore, it was examined the existing design and construction standards, analyzed the cause through accident examples of the curved section of the Block Type MSE wall. As a result, the horizontal displacement of the curved section was 90% higher than that of the straight section and 60% higher than that of the concave section. In the case of the convex section in the curved section reinforcement region, the maximum displacement is shown in the H/2 section in the horizontal direction from the center of the MSE wall, and the range of influence from H is shown. In the case of the concave section, the maximum displacement is shown in the center, The minimum displacement was confirmed in H/4 section in the horizontal direction from the center of the MSE wall. As a basic study on the reinforcement area rehabilitation through the actual construction of block type MSE wall, the behaviors of the straight part and the curved part were compared and analyzed. And analyzed the reinforced area in order to reduce the damage of the stress concentration phenomenon and secure the safety.