• 한국방재안전학회논문집
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• 제14권3호
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• pp.51-63
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• 2021

본 연구는 도심지 지하 교통망 건설 중 터널굴착 공정에 적용하는 차수·보강 그라우팅 공사의 품질향상을 위한 것이다. 기존의 터널 그라우팅 시공에서는 실시간으로 주입압 및 주입량을 보여주는 P~q~t charts를 기술적으로 온전히 활용하지 못하였다. 그 이유는 주입지반의 차이 및 주입 중 어떤 문제가 발생할 시에 P~q~t charts가 어떻게 변화하며, 그에 따른 표준적인 주입유형을 보여주는 주입 그래프 패턴, 특성, 판정, 그에 따른 조치유형 및 조치방법에 대한 기술적 판단방법이 없었기 때문이다. 본 논문은 상기의 문제점 등을 해결하기 위한 일환으로 일반 및 알고리즘 그라우팅 시 토사층 및 암반층으로 구분하여 주입유형, 특성, 판정방법, 그리고 조치유형 및 조치방법 등의 연구를 수행하였다. 새롭게 개선된 토사층 P~q~t charts에서는 일반그라우팅과 알고리즘 그라우팅 둘로 나누어 각각 6가지 유형으로 구분하였고 각 유형에 따른 특성 및 판정방법을 도출하였으며 일반주입유형과 알고리즘 주입유형에서의 각 유형별 조치방안도 개발하여 현장에서 쉽게 적용 가능하도록 제안하였다. 또한, 개선된 암반층 P~q~t charts에서도 각각 6가지 유형으로 구분하여 토사층과 같이 해당 유형에 상응하는 조치방안을 개발하여 현장에서 쉽게 적용 가능하도록 제안하였다. 따라서, 도심지 지하 교통망 건설 중 터널굴착 공정에 적용하는 차수·보강 그라우팅 공사에서 예비단계의 현장시험 혹은 시공 중 단계에서 시간에 따른 주입압 및 주입량의 데이터인 P~q~t charts를 실시간 측정하여 주입유형을 분석하고 조치방법을 마련하여 더 나아가 모든 그라우팅 단계에서 활용될 수 있을 것으로 기대된다.

• 지질공학
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• 제11권1호
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• pp.81-99
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• 2001

터널의 차수그라우팅 효과를 확인하기 위하여 영천댐 도수터널 건설공사 중에 현장 그라우팅 시험을 수행하였다. 시험은 그라우팅 시기에 따라 굴착전, 굴착후 및 콘크리트 라이닝일 설치된 이후의 압밀 그라우팅 등으로 구분하였고, 주입재료, 암종 및 지질인자, 그라우팅공의 천공방향 및 주입단계에 따른 효과를 비교하도록 계획하였다. 재료의 특성에 따른 차수효과는 포틀랜드시멘트, 마이크로시멘트, 마이크로시멘트 마이크로시멘트+규산에 비해 우레탄이 가장 뛰어났으며, 시공시기에 따라서는 라이닝후 및 굴착후에 비해 굴착전 그라우팅시 차수효과가 뛰어났다. 암종에 따라서는 화산암 및 화강암지반에 비해 퇴적암지반에서 차수효과가 낮게 나타났는데 이는 퇴적암에 발달하는 절리틈새가 적고 절리 충전물이 많아서 주입재의 침투성 저조에 기인한 것으로 사료된다. RMR값과는 직접적인 상관성이 없으나 RMR 요소 중 절리틈의 간극이 클수록 차수효과가 높게 나타났다. 천공방향은 차수효과에 영향을 미치지 않았으나 주입방법은 천공 및 주입의 단계를 세분할 수록 높은 차수 효과를 기대할 수 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.368-375
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• 2009

This paper describes field installation and load test results performed for three types of micropiles in the process of developing a new micropiling method. Field tests were performed for two conventional types(i.e., micropile reinforced with steel bar and gravity grouting, micropile reinforced with steel bar and steel casing and gravity grouting) and a proposed type(i.e., micropile reinforced with hollow steel pipe wrapped with geotextile-pack and pressurized grouting). The load test results subjected to axial compression and tension and lateral loading conditions are described in this paper. The micropiles were exposed in the air in order to verify the installation quality and curing condition of grouting material via ground excavation. Axial compression and tension test results indicate that the new micropile type provide at least 40% higher bearing capacity than that of conventional types. Based on the examination of exposed piles, it is induced that the proposed method, packed micropile, provides better interlocking between grouts and surrounding soils and increases higher frictional resistance comparing to conventional types.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권1호
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• pp.35-42
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• 2019

In installation of groundwater wells, grouting materials are injected between the groundwater borehole and the inner casing in order to prevent infiltration of contaminated groundwater from the top soil layers into wells. The injection device of grouting materials is commonly composed of an inlet head device with an expansion packer, a cylinder capable of storing the grouting materials, and an air cylinder. In this work, two types of common grouting materials, silicon and cement materials, were tested for their performances as grouting media. For silicon. silicon was mixed with clay or calcite, and tested for their tensile strength and underwater reactivity. Both silicon-clay and silicon-calcite mixtures had adequate flow and adhesiveness. For cement material, general cement, ultra-rapid harding cement, and natural cement were respectively mixed with three different soil types including coarse-grained granite, fine-grained granite, and gneiss, and direct shearing tests were conducted after hardening. Under grouting depth condition of 30 m, the minimum adhesive strength was greater for weathered gneiss than non-weathered gneiss with its maximum values obtained from the mixtures of ultra rapid-harding cement.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.899-904
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• 2009

This paper presents the analysis result of load-transfer mechanism and pile movements associated with the development of frictional resistance to understand the engineering characteristics of micropile behavior. An field load tests were performed for two different types of micropiles and they are (i) thread bar reinforcement with D=50mm and (ii) hollow steel pipe reinforcement with $D_{out}$=82.5mm and $D_{in}$=60.5mm and wrapped with woven geotextile for post-grouting. The load test results indicated that micropiling with pressured grouting provided better load-transfer characteristics than micropiling with gravity grouting under both compressive and tensile loading conditions in that unit skin frictional resistance is well distributed along installation depth. The unit weight and unconfined compressive strength of cured grout were obtained for each piling method. The strength and unit weight of micropile with pressured grouting was higher than those with gravity grouting. The fact that load bearing quality with pressured grouting is better than that of gravity grouting could be attributed to the dense mutual adhesion between surrounding ground and pile due to pressurized grouting method and better grout quality.

• 한국지반공학회논문집
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• 제33권9호
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• pp.23-34
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• 2017

도심지 지하공간 개발을 위해서는 안정성 확보를 위해 암반 또는 암주의 미세균열까지도 보강해야 한다. 본 논문에서는 그라우팅 재료의 점도 및 입경, 주입압력, 균열 폭 등을 고려한 미세균열 그라우팅의 주입성능에 대한 연구를 수행하였다. 미세균열 보강에 사용되는 대표적인 그라우팅 재료는 용액형인 약액형 그라우팅 재료와 현탁액형인 시멘트계 그라우팅 재료가 있다. 약액형 그라우팅 재료와 시멘트계 그라우팅 재료의 주입성능은 공통적으로 점도에 영향을 받으며, 시멘트계 그라우팅 재료의 주입성능은 추가적으로 주입 재료의 입경에 영향을 받는다. 실내실험을 통해 점도를 역계산하여 재료별로 적합한 점도 측정 방법을 제시하였고, 균열 폭과 재료의 입경 간의 관계를 이용한 groutability ratio로 시멘트계 그라우팅 재료의 그라우팅 가능여부를 평가하였다.

• 한국지반환경공학회 논문집
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• 제3권4호
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• pp.37-49
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• 2002

본 연구에서는 고강도 고내구성 및 환경에 대한 안정성이 높은 주입재료를 주입재 형태별로 즉 현탁액형, 용액형 주입재에 배합설계를 실시하여 주입압, 지반조건에 따른 주입효과와 환경적 유해성을 분석 검토하고자 한다. 주입재 특성 및 주입효과에 대한 연구결과, 현탁액형 주입재에서는 초미립자시멘트가 보통시멘트에 비하여 상당히 높은 침투성 및 고결율을 나타냄을 알 수 있었고 용액형 주입재에 사용된 인산과 탄산수소나트륨의 경우 초미립자시멘트와 유사한 경향을 나타내었다. 주입된 고결체의 압축강도 시험결과, 현탁액형 주입재의 초미립자시멘트가 상당한 고강도를 나타났으나 용액형 주입재의 경우 현탁액형 주입재에 비하여 매우 낮은 강도를 나타내었다. 또한 주입재가 가지고 있는 환경적 유해성 여부를 평가하기 위해 대상시료를 주입재의 원재료 및 주입재의 고결시편의 양생일수에 따라 중금속 용출시험을 실시한 결과, 선정한 약액조합 및 고결체의 중금속 함량은 규제기준을 만족하였다.

• Smart Structures and Systems
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• 제33권1호
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• pp.41-53
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• 2024

Grouting sleeves are an essential connecting component of prefabricated components, and the quality of grouting has a significant influence on structural integrity and seismic performance. The embedded grouting sleeve (EGS)'s grouting defects are highly undetectable and random, and no effective monitoring method exists. This paper proposes an ultrasonic guided wave method and provides a set of guidelines for selecting the optimal frequency and suitable period for the EGS. The optimal frequency was determined by considering the group velocity, wave structure, and wave attenuation of the selected mode. Guided waves are prone to multi-modality, modal conversion, energy leakage, and dispersion in the EGS, which is a multi-layer structure. Therefore, a time-reversal (TR)-based multi-mode focusing and dispersion automatic compensation technology is introduced to eliminate the multi-mode phase difference in the EGS. First, the influence of defects on guided waves is analyzed according to the TR coefficient. Second, two major types of damage indicators, namely, the time domain and the wavelet packet energy, are constructed according to the influence method. The constructed wavelet packet energy indicator is more sensitive to the changes of defecting than the conventional time-domain similarity indicator. Both numerical and experimental results show that the proposed method is feasible and beneficial for the detection and quantitative estimation of the grouting defects of the EGS.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.85-92
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• 2003

Generally, ordinary portland cement(OPC) is widely used for grouting to reduce permeability of ground under the foundations of structures. But, it is hard to be injected into the microscopic voids, fissures and crevices in soil or rock formation for the OPC material. Therefore new method what is called MSG(Micro Silica Grouting) has been developed recently to improve the weak point of the OPC material. In this case study, in order to verify performance of the MSG's water cut-off, trial injections were performed in rear of CIP(Cast in Place Pile) on the site A(weathered soil) and B(alluvial soil) that are constructed for the subway No. 9 nowadays. To take the proper grouting method of the MSG in the trial injecting, the injections are carried out for grouting types(constant pressure or fixed Quantity) and grouting methods(1.5shot or 2.0shot) and to confirm the effects of water cut-off and the injection range of the MSG, the tests of permeability and indicator(phenolphthalein) response were performed before and after the injection. Through the tests results, we could affirm the effects of water cut-off of the MSG and the injection range for the weathered and alluvial soil layers near the Han River. Finally we could make sure the application of the MSG method in actual construction under the layers.

• 보존과학회지
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• 제36권4호
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• pp.284-295
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• 2020

This study focuses on reinforcement agents for wall damage, such as cracks, breakage, or delamination, for mural paintings from the Payathonzu temple. Experiments were conducted with filling and grouting agents based on the reinforcing method. In the filling reinforcement experiment, different mixing ratios of lime to sand, and additives (jaggery, seaweed glue, and Primal SF-016) were used. In the grouting reinforcement experiment, the mixing ratio of lime and pozzolan was the same, and the additive types were identical to the filling reinforcement experiment. The filling reinforcement experiment showed that there were fewer physical changes such as contraction, with a greater mixing ratio of lime to sand, however, the compressive strength decreased as the mixing ratio increased. With additives, the change in volume of agent decreased and the compressive strength increased, which was especially prominent for jaggery and Primal SF-016. The grouting reinforcement experiment showed that there was a remarkable contraction with an increased amount of moisture that originates from the characteristic of grouting agents that requires flowability. With additives, the water content of the agent decreased, whereas the compressive strength and adhesion increased. Among the additives, Primal SF-016 exhibited the highest compressive strength, and seaweed glue exhibited the most considerable viscosity and adhesion. The study results showed that the characteristics of reinforcement agents vary according to the mixing ratio and additives of the filling and grouting agents. Therefore, it is necessary to selectively apply the mixing ratio and additives for different reinforcement agents considering the wall damage for conservation treatments.