• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.83-89
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• 2012

Anchor, soil nail and micropile have been widely used for slope reinforcement and foundation. These all methods need grouting work after placing reinforcing member. The pressure injection-grouting techniques helps to increase the bearing capacity of reinforcing member by enhancing larger effective pile diameter and increasing the radial stresses acting on the grout body and causing irregular surface. However, the pressure reinjection-grouting techniques is not commonly used because grouting equipment and practical application example are short and the verification of reinforcing effect is difficult. In this study, the laboratory test was performed to evaluate the reinforcing effect with variation of grouting methods in clay. As a result of the test, the pressure reinjection-grouting techniques showed that the pullout capacity of reinforcing member increased up to 1.22~2.61 times comparing to the gravity fill techniques.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.63-74
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• 2012

In Korea, grouting has been mostly designed and constructed by experiences without expert knowledge and theoretical study. So there are a lot of problems related to the quality and safty of grouting. Therefor, in this paper the quality management skills and method were discussed through out by using the auto-grouting method and field test of grouting for the construction. Through the limit water injection test of the soil, it make the optimum injection pressure and injection speed of grouting, and through the lugeon test of the rock, it make assess the permeability of before and after grouting. In order to prevent the hydraulic fracture of soil and break away from the grouts if it apply four kinds of mode of grouting stop criteria, injection effects can be improved. From the above characteristcs designers evalute the fitness values of injection pressure(p), injection speed(q) and grouting penetration time(t). So far, to record and manage pressure(p) and speed(q) of grouting autographic devices such as intergation flow-meter usually record data in a roll of paper. Intergration flow-meter can record grouting flow quantity exactly, but the recorded pressures differ from the any basis such as intitial, intermediate and final point. Therefore, it has been argued that is a need of reliable method to describe the connection between the pressure recorded by an intergration flow-meter and the special properties of the grouting target ground. auto-grouting method can describe the reliable connection between the grouting pressure and the special properties of the grouting target ground. So, in this paper by using auto-grouting method, it is expected that to secure basis of quality control techniques construction.

• Journal of the Korean GEO-environmental Society
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• v.11 no.10
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• pp.25-31
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• 2010

Anchor, soil nail, micropile have been widely used for slope reinforcement and foundation. These all methods need grouting work after placing reinforcing member. In domestic case, gravity fill techniques and pressure grouting techniques are mainly used. In contrast the pressure re-injection grouting method is not commonly used because grouting equipment and lack of practical application example is short and the verification of reinforcing effect is difficult. Pressure re-injection grouting is a kind of post grouting which technique increases the radial stresses acting on the grout body and causes irregular surface to be developed around bond length that tends to interlock the grout and the ground. In this study, the field test was performed to evaluate the reinforcing effect with the variation of grouting methods and pullout characteristics of reinforcing member placed by pressure re-injection grouting method. The test results showed that the post-grouting methods were useful to increase the pullout capacity.

• Journal of the Korean Geotechnical Society
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• v.30 no.3
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• pp.5-16
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• 2014

Soil-nailing has two main resistance factors: skin friction between ground and grouting; and tension load of reinforced material. These two factors will affect the load-displacement curve when performing soil-nailing pullout tests. The purpose of this paper is to figure out the shear behavior between ground and soil-nailing focusing on the net load-displacement behavior during soil-nailing pullout tests. Firstly, the net load-displacement curve between ground and grouting is estimated theoretically. Then, in-situ pullout load tests are performed on various ground conditions to obtain the load-displacement curve occuring between ground and grouting. Since the measured shear displacement includes elongation of the reinforced material (steel nails), the net load-displacement curve can be obtained by subtracting the elongation magnitude of steels from the measured displacement. It was found that the measured net load-displacement curve matches reasonably well with the theoretically estimated curve.

• Journal of the Korean GEO-environmental Society
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• v.10 no.2
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• pp.51-59
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• 2009

This study is based on field data obtained from rock grouting such as RQD value, Unit cement grout volume, Lugeon value(Lu), and Maximum grout pressure in four different dam sites. The relationship were analyzed and compared as follow. The cut-off effect after rock grouting in dam-foundation which are mostly consist of metamorphic rock is better than that of Sedimentary rock. And the impermeable effect after consolidation grouting is more efficiency than the impermeable effect after curtain grouting. The unit cement grout volume are increased as RQD value is higher in rock mass. But there is no relationship between RQD value and Lugeon value. In the sedimentary rock, which is more permeable than metamorphic rock, Lugeon value (Lu) is a linear function (Lu=0.22Vc) of unit cement grout volume (Vc). Cut-off effect of curtain grouting is less influential at each near holes which are already grouted than that of consolidation grouting. And the behavior characteristics of Lugeon value vs. the unit cement grout volume as the order of installations are almost the same.

• Journal of the Korean GEO-environmental Society
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• v.12 no.9
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• pp.79-87
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• 2011

This study conducted the research on the method of grouting quality management and the improvement effect by applying grouting construction's quality management technology to automatic injection management equipment through measure of liquefaction based on the case of reinforcement applying grouting at the region where liquefaction happened at section 12 site of highway construction. The pressure(p), speed(q), grouting penetration radius(R) value from injection pressure, injection speed, characteristics of grain size, and characteristics of viscosity through p-q-t chart analysis was applied to the automatic grouting system which could improve the quality management of grouting. Standard penetration test results after injection showed that N values represented 5-20 and the prevention of liquefaction became possible.

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.165-180
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• 1999

Static load tests were performed for open-ended piles, closed-ended piles, piles with grouted toe, and base-grouted piles by using calibration chamber. Then vertical bearing capacities determined from load tests were compared with each other. The stability of base-grouted pile during a simulated seaquake was investigated by changing the penetration depth. Also, static load tests and seaquake tests for 2-piles and 4-piles group were performed. The bearing capacity of the pile grouted inside the toe was 11.2~30.8% less than that of open-ended pile because of reduction of base resistance due to disturbance of base soil under pile toe. The bearing capacity of a base-grouted pile was 23.8~33.9% more than that of an open-ended pile and was similar to that of a closed-ended pile. The bearing capacity of base-grouted group pile was increased ; the bearing capacity of base-grouted 2-piles group increased 14.6~31.8% compared to that of open-ended 2-piles group, and that of base-grouted 4-piles group increased 15.3~22.4% compared to that of open-ended 4-piles group. During the simulated seaquake in deep sea, stability of base-grouted pile was found to be dependent on the pile penetration depth. During seaquake motion, single long base-grouted pile longer than 20m was stable and short base-grouted pile shorter than 12m failed. But relatively long base-grouted pile longer than 12m kept mobility state. Bearing capacity of base-grouted group pile with penetration depth less than 7m was degraded a little bit ; so, base-grouted group pile could maintain mobility condition.

• Geotechnical Engineering
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• v.27 no.3
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• pp.29-39
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• 2011

• Land and Housing Review
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• v.12 no.4
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• pp.127-137
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• 2021

Grouting has been widely used to enhance the strength of the ground and prevent waterflow into the underground space in the geotechnical engineering field. Cement with bentonite can be considered a helpful grouting material because the bentonite has a swelling ability with water. Therefore, it is essential to evaluate the characteristics of grouting materials according to the mixing ratio for a successful grouting process. In this regard, the study investigated the viscosity and bleeding characteristics of grouting materials according to the mixing ratio (i.e., water/cement ratio and bentonite/cement ratio). In the experimental result, the viscosity increases with decreasing water/cement ratio and rising proportion of bentonite by weight of cement. However, the results of the bleeding ratio show the tendency is inversely proportional to the viscosity results. Bentonite was explored in terms of the viscosity and bleeding criterion. This result is expected to be meaningful to determine the optimized mixing ratio of bentonite-cement in the grouting field.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.375-392
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• 2018

The shield TBM method is widely adopted for tunneling works in urban area because it has more beneficial ways to control settlement at ground surface than conventional mined tunneling. In the shield tunneling, backfill grouting at tail void is crucial because it is supposed not only to restraint ground deformation around tail void during excavation but also to compensate precedent ground settlement by pushing up the ground with highly pressurized grout. However, the tail void grouting has been found to be ineffective for settlement compensation particularly in sandy ground, which might be caused by complicate interaction between ground and tail void grouting. In this paper, the effects of tail void grouting on behavior of ground in shield TBM tunneling were investigated based on 3-dimensional finite element analyses. The results of numerical analyses indicated that backfill grouting actually reduces settlement by degrading settlement increasing rate in excavation, which means decrease of volume loss. Meanwhile, the grouting could not contribute to compensate the precedent settlement, because reduction of volume loss by grouting was found to be counterbalanced by volume change of ground.