• Journal of the Korean Geotechnical Society
• /
• v.20 no.6
• /
• pp.19-27
• /
• 2004

Since the first construction of soil nailing in France in 1972, the application of soil nailing has increased. However, there is currently no design method which is universally accepted or agreed upon far soil nailed wall, because each of the design methods has different assumptions and, therefore, different approaches, moreover, since the suggested optimal inclination angles of nails are different by researchers. Therefore, the effect of nail inclination with soil nailing is analyzed by FEM. In this study, Finite element program SOILSTRUCT was applied for the effect analysis of nail inclination in soil nailed wall. For this finite element analysis, CEBTP No. 1 project data were used. The analyzed nail inclination ranged from 0$^{\circ}$ to 30$^{\circ}$ with 5$^{\circ}$ intervals. The result of finite element analysis showed that the most optimal inclination was 20$^{\circ}$ Also, the tension farce in the nails increased as the nail inclination increased. However, the effect of nail inclination on the wall deformation was very little. Therefore, constructability seems to be more important than nail inclination. Also, the tension force in the nails increases as the nail depth below the top of the wall increases, except f3r the lowest nail. Therefore, appropriate nail diameter should be used to prevent breakage of nails with considering nail strength-deformation interaction.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.12
• /
• pp.5963-5973
• /
• 2011

Current design and analyzing methods about soil nailing structures, developed on the basis of results obtained from experiments in laboratory or in field and numerical analyses, have applied different interaction mechanisms between the reinforced nails and the surrounding ground, and different safety factors against failure have been obtained. They might be proper approaches if the assumptions about rigidity of nails and ground conditions are met with actual conditions occurred in field. Otherwise, they would result in designing on analyzing in inappropriate ways so that it is needed to evaluate the validity of them. Therefore, in this research using the Centrifugal Model Testing, numerical parameters experiments about soil nailing structures' behavior and failure mechanism were performed. In the numerical parameters experiments, transmuted nail's length, setting angle, nail's front panel, stiffness variously, and increased the level of gravity until wall model was destroyed. Based on experimental results, we compared the effect, failure mechanism caused from parameters changes. By reviewing and comparing centrifugal model test results and methods currently in use, verified validity of existing methods.

• Journal of the Korean GEO-environmental Society
• /
• v.22 no.2
• /
• pp.5-13
• /
• 2021

In this study, as the production of high-strength steel pipes due to the development of steel materials, the stability and applicability of the soil nailing method using high-strength steel pipes were evaluated. Rebars used as reinforcement in the soil nailing method are the same in order to determine the behavioral characteristics and the effect of increasing the reinforcement when replacing it with a high-strength steel pipe of a diameter, a field test were conducted to confirm the stability. As a result of the tensile test, the measured strain is smaller than the strain in the theoretical equation, so it can be seen that the behavior is similar to that of the soil nailing method using rebars. As a result of the displacement measurement, the displacement of the high-strength steel pipe is larger than that of the rebars is considered to be the effect of the internal grouting effect of the steel pipe and the decrease in the cross-sectional area. In the case of using high-strength steel pipes for the soil nailing method, it is judged that the field applicability is good by improving stability and workability through member performance and weight reduction.

• Journal of the Korean GEO-environmental Society
• /
• v.5 no.2
• /
• pp.41-49
• /
• 2004

In this study, a newly modified soil nailing technology named as the SPN (Spiral Pipe Nailing) system, is developed to self drilling method can apply to ground which is hard to keep shape of bore hole. And limit equilibrium analysis with simplified trial wedge method while length ratio and bond ratio being altered was performed to evaluate slope stability considered of tensile strength and bending stiffness. Also, using $FLAC^{2D}$ program, superiority of the SPN system was compared to the GSN (General Soil Nailing) system about an example section. And effects of various factors related to the design of the SPN system, such as the type of drilling method and the bit, are examined throughout a series of the displacement-controlled field pull-out tests. As a result, the SPN system is better than the GSN system in slope stability because of having larger bending stiffness, tensile strength and unit skin friction. And results of simplified trial wedge method are similar to results of TALREN 97 program, commercial limit equilibrium analysis computer software, about an example section. Consequently, it will find out of that the SPN system reduce displacements and settlements in down excavation process as well as to increase the global stability.

• Geotechnical Engineering
• /
• v.13 no.2
• /
• pp.91-100
• /
• 1997

The soil nailing method has been developed on the basis of experimental works as well as theoretical backgrounds. As for the experimental research works, most of the data have been measured during the application of load in service. However, not only the soil-nailed structure behavior in service but also the failure behavior of the structure is major concern to evaluate and even establish a design method of soil-nailed walls. In this study, a relatively large-scale experiment was carried out to figure out the failure behavior of soil-nailed wall. A number of data such as displacement of soil-nailed walls, soil pressure in soil-nailed walls, atrial strain and axial force of nail etc.'have been acquired and analysis.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2004.03b
• /
• pp.301-310
• /
• 2004

The several computer programs for the design of soil nailed wall are often used in Korea. However, these programs have been used without and practical justification. Therefore, in order to evaluate the applicability of these programs for the design of soil nailing, these computer results were analyzed and compared with one another. The performance evaluations by the available programs, such as SNAILZ, TALREN97, SLOPE/W STABL6, and NAILMI6, were applied and the applied data were from 6 case history(21 section). The estimated factors of safety with available programs were compared with observed horizontal deformation from the field. This study showed that the program SNAILZ is most adequate tool for the design of soil nailed wall. Also, The finite element program SOILSTRUCT was applied for the analysis of nail inclination effect in soil nailed wall. The program SOILSTRUCT showed that the most optimal inclination of nail was $20^{\circ}$. However, the effect of nail inclination on the wall deformation was negligible. Also, the tension force of the nail were increased as the nail inclination increased, and the tension force of the nail increased as the depth increased, except the deepest nail. Therefore, the larger diameter nail should be considered if the inclination of nail is steeper than the suggested range, and the deeper nails should have the larger diameters than those of shallower nails except for the deepest one.

• Journal of the Korean Geosynthetics Society
• /
• v.9 no.4
• /
• pp.1-7
• /
• 2010

The soil nailing method have been developed on the basis of experimental works as well as theoretical backgrounds. As for the experimental research works, most of the data have been measured during the application of load in service. However, not only the soil-nailed structure behavior in service but also the failure behavior of the structure are the major concerns to evaluate and even establish a design method of soil-nailed walls. In this paper for the apprehension of behavior in the soil-nailed structure which the front of nail is connected, a relatively large-scale experiment was carried out to figure out the failure behavior of soil-nailed wall. A number of data have been acquired and analysis.

• Journal of the Korean GEO-environmental Society
• /
• v.5 no.1
• /
• pp.47-54
• /
• 2004

The several computer programs for the design of soil nailed wall are often used in Korea. However, these programs have been used without any practical justification. Therefore, in order to evaluate the applicability of these programs for the design of soil nailing, these computer results were analyzed and compared with one another. The performance evaluations by the available programs, such as SNAILZ, TALREN97, SLOPE/W, STABL6, and NAILM16, were applied and the applied data were from 5 case history(15 section). The estimated factors of safety with available programs were compared with observed horizontal deformation from the field. The results showed that the program SNAILZ is most adequate tool for the design of soil nailed wall.

• Geotechnical Engineering
• /
• v.14 no.3
• /
• pp.73-94
• /
• 1998

In the present study, a method of the three-dimensional limit equilibrium stability analysis of shape of the potential failure wedge for the concave-shaped excavation corner is assumed on the basis of the results of the FLACSU program analysis. Estimation of the three-dimensional seepage forces expected to act on the failure wedge is made by solving the three-dimensional continuity equation of flow with appropriate boundary conditions. By using the proposed method of three-dimensional stability analysis of the concave-shaped excavation corner, a parametric study is performed to examine the reinforcement effect of skew soil nailing system, range of the efficient skew angles and seepage effect on the overall stability. Also examined is the effect of an existence of the right-angled excavation corner on three-dimensional deflection behaviors of the convex-shaped skew soil nailing walls. The results of analyses of the convexshaped excavation corner with skew soil nailing system is further included to illustrate the effects of various design parameters for typical patterns of skew nails reinforcement system.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.03a
• /
• pp.744-751
• /
• 2006

In case of the Soil Nail System applied to a slope, effects of vibrations from blasting, earthquake and creep of long term behaviors cause reductions of adhesion between grout and soil-nail. There are some reports of nail's pull-out failure by those reasons. In this paper it is suggested that the Cone Nailing System is enable to diminish effects of vibrations and creep. In this study on Cone Nailing System, the cones are installed to each nail by 2m. By such installing cones, the adhesion between nail and grout will increase and the long term creep behavior will decrease. In this study, the centrifuge test is performed to understand the behaviors of the Cone Nail System. For the centrifuge test, the soil tank is 52cm in width, 17cm in length and 35cm in height. In comparison with general soil nail, the centrifuge test of general soil nail(without cone) is performed equally. Additionally, the interface between cone nail and soil through the pull-out test is applied to FLAC 2D version 3.3. and the evaluation of application for the Cone Nail System in slope is performed.