• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 봄 학술발표회 논문집
• /
• pp.183-190
• /
• 2000

Effective range of Hydraulic Hammer Compaction was studied by numerical analysis instead of empirical method. Numerical analyses were carried out with commercial FEM code, ABAQUS, and verified by comparing the numerical results with field tests of Hydraulic Hammer Compaction. Most of material properties were evaluated by data from laboratory and in-situ tests. Vertical effective range was estimated by distribution curve of plastic strain energy dissipated through soil layers under dynamic load and these results were in good agreement with field tests. Based on verification, the effects of governing properties of Hydraulic Hammer Compaction such as number of hit can be determined by numerical analyses. In addition, vertical effective range can also be determined by Menard's empirical equation using the external work at converging time of plastic strain energy in numerical analysis. This implies that the minimum energy of Hydraulic Hammer Compaction for improvement can be determined by Menard's equation.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.910-921
• /
• 2004

In this study, the pilot tests on the reclaimed land were performed in order to find the suitable construction method with dynamic compaction Type I, Type II at different dynamic energy and hydraulic hammer compaction. The estimation of the compaction through the various pilot tests was performed by the CPT-qc, SPT-N and field density tests. As the result of the pilot tests, it shows that the dynamic compaction method is better than the hydraulic hammer compaction method in the effect of the ground improvement, especially dynamic compaction Type I is much superior to others. When it comes to method for measuring the intensity of the ground, the value of the cone penetration test-resistance(qc) is much suitable for the ground. Besides, the standards for the compaction control, which showed that over 10Mpa at 0 through 5meters in the upper layer and 7Mpa at 5 through 8meters in the lower layer in the CPT-qc, could be found without discrimination of the upper road and lower road on the reclaimed land. And it also found that the intensity of the reclaimed land gets back to the original status in about 10 through 15 days.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1999년도 봄 학술발표회 논문집
• /
• pp.455-462
• /
• 1999

In this case, we have selected a representative location in the vicinity of large underground structures where they cross a runway and taxiway: measured the effects of the dynamic hammer compaction by distance: analyzed the measured results over a period of time and for many frequencies: and determined the maximum anticipated particle velocity (PV) of vibration, caused by the dynamic hammer, verses distance. In addition, while compacting the hydrofill, we reviewed the impact of subsurface particle velocities, caused by hammer compaction methods, upon newly constructed reinforced concrete underground structures. We have implemented the appropriate technical standards after reviewing domestic and international technical standards concerning allowable vibration velocity appropriate In the many types of underground structures at Inchon International Airport.

• 한국산업융합학회 논문집
• /
• 제7권4호
• /
• pp.341-348
• /
• 2004

This study experimented dividing compaction load by dynamic compaction test and an oil pressure hammer compaction test for consolidation strength characteristics experimental feedback about soil change aspect of waste landfill ground and revelation of compaction effect as underground research about consolidation behavior of waste landfill ground by compaction load, foot weight and percussion number of times were adapted differently each other with uniformity drop head when dynamic compaction test, and hammer scale and percussion number of times were adapted differently also when oil pressure hammer compaction test.

• Geomechanics and Engineering
• /
• 제10권1호
• /
• pp.109-124
• /
• 2016

In this paper, process of dynamic powder compaction is investigated experimentally using impact of drop hammer and die tube. A series of test is performed using aluminum powder with different grain size. The energy of compaction of powder is determined by measuring height of hammer and the results presented in term of compact density and rupture stress. This paper also presents a mathematical modeling using experimental data and neural network. The purpose of this modeling is to display how the variations of the significant parameters changes with the compact density and rupture stress. The closed-form obtained model shows very good agreement with experimental results and it provides a way of studying and understanding the mechanics of dynamic powder compaction process. In the considered energy level (from 733 to 3580 J), the relative density is varied from 63.89% to 87.41%, 63.93% to 91.52%, 64.15% to 95.11% for powder A, B and C respectively. Also, the maximum rupture stress are obtained for different types of powder and the results shown that the rupture stress increases with increasing energy level and grain size.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
• /
• pp.1178-1187
• /
• 2008

Quality assurance for embankment compaction is one of very important procedures to guarantee high quality construction. However, only sand replacement method (KS F2312) and static plate load test (KS F2310) which are conventional and tiresome methods are used to evaluate degree of compaction at construction fields. Recently, new types of devices such as the geogauge and the light falling weight deflectometer (LFWD), the soil impact hammer (CASPFOL) and dynamic cone penetration test etc. which are able to substitute for the conventional methods are begun to use to evaluate soil stiffness. In this study, a laboratory model test was performed to evaluate correlations among test results obtained from the new devices and to assess the potential use of them. All test results have correlations with relative density and water content. Especially, the coefficients of correlation between $E_G$ from the geogauge and $K_{30'}$ from the soil impact hammer and between $E_G$ from the geogauge and $E_{LFWD}$ from LFWD are more than 0.7 but those between the results from DCP and others are less than those between $E_{G{\cdot}}$ and $K_{30'}$ and $E_G$ and $E_{LFWD}$.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
• /
• pp.636-643
• /
• 2008

본 연구에서는 지오게이지, 동평판재하시험기 그리고 간이지지력시험기 등과 같은 지반강성도를 평가할 수 있는 시험장치와 현장 다짐도 측정에 가장 많이 사용되는 평판재하시험을 다짐횟수, 함수비 그리고 다짐층 두께 등을 변화해 가면서 현장시험을 수행한 결과, 다음과 같은 잠정 결론을 내릴 수 있었다. 1) 지오게이지와 동평판재하시험기 그리고 간이지지력 시험기에서 측정된 결과는 모두 다짐도 증가에 따른 지반 강성 증가 현상을 잘 반영하는 것으로 나타났다. 2) 함수비에 따른 지반강성 증감 현상은 지오게이지와 간이지지력시험 결과에서만 일부 뚜렷하게 나타났으며, 동평판재하시험이나 기준 시험인 평판재하시험은 함수비 증감에 따라 지반강성 증감 현상이 뚜렷하게 나타나지 않았다. 3) 다짐충 두께 변화에 따른 지반강성도 평가시험 결과 본 시험에서 수행한 지오게이지, 동평판재하시험, 간이지지력 시험은 물론 기준시험인 평판재하시험의 경우에도 일정한 경향이 뚜렷하게 나타나지 않아 이에 대한 추가적인 연구가 필요할 것으로 판단된다. 본 연구에서는 간편하고 신속한 시험이 가능한 다양한 지반강성평가 시험장치를 이용해 현장에서 다양한 조건의 지반에 대해 다짐도 평가 시험을 수행한 결과, 함수비 및 다짐두께가 일정한 경우 다짐횟수 증가에 따라 모든 시험 결과가 지반강성도가 증가하는 것으로 나타났다. 따라서, 추후 다양한 지반조건에 대해 다양한 시험을 수행하여 다짐도 및 지반강성도의 연관성에 대한 자료가 축적된다면, 본 시험에서 수행한 시험방법으로도 현장 다짐도 측정이 가능할 것으로 판단된다.

• 한국도로학회논문집
• /
• 제17권3호
• /
• pp.35-47
• /
• 2015

PURPOSES : A tack coat has been utilized to increase the bond performance between the surface layer and base course (intermediate course) at various road pavement sites. This is similarly true in other nations. Based on this connection, the objective of the present study is to evaluate the properties of hot mix asphalt (HMA) mixtures with an RSC-4 or BD-Coat and determine the application rate of the tack coat. METHODS : The HMA specimens were manufactured using superpave gyratory compaction. The HMA mixtures were composed of a 5-cm thick surface layer and a 10-cm thick base course. An impact hammer resonance test (IHRT) and a static load shear test were conducted to evaluate the performance of the HMA mixtures with a tack coat. From these tests, the dynamic moduli related to the high-frequency resistance and interlayer shear strength (ISS) of HMA could be obtained. RESULTS : The results of the dynamic moduli of HMA are discussed based on the resonance frequency (RF). To check the accuracy of the IHRT, we conducted a coherence analysis. A direct shear test using the application of a static load test was carried out to evaluate the interlayer shear strength (ISS) of HMA. CONCLUSIONS : The maximum ISS was demonstrated at an RSC-4 application rate of 462 gsm, and the maximum dynamic modulus was demonstrated at an RSC-4 application rate of 306 gsm. By averaging the results of the ISS, the maximum ISS values were obtained when a BD-Coat application rate of 602 gsm was applied.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 추계 학술발표회
• /
• pp.519-526
• /
• 2010

The construction site for $\bigcirc\bigcirc$ transformer substation was located at a mountain valley. In order to prepare the site, the valley was first filled with crushed rock debris up to 63m. Since the main concern of this project is to minimize differential settlement of the foundation of transformer facilities, dynamic compaction was performed every 7m followed by reinforcement with EMP(Ez-Mud Piling). The EMP is one of bored piling methods, in which a hole is bored by means of air percussion and maintain by injecting Ez-Mud. Then a PHC pile (Pretensioned spun High strength Concrete pile) is embedded and finalized with a hammer. In this study, bearing capacities and long term behavior of a pile installed by EMP were investigated. To achieve these objectives, a series of tests such as static and dynamic load tests were conducted. In addition, a construction quality control standard was proposed based on the test results.

• 한국산학기술학회논문지
• /
• 제8권5호
• /
• pp.1152-1158
• /
• 2007

현재 미국, 유럽, 일본 등을 중심으로 기존의 다짐평가시험보다 빠르고 간편하게 다짐도를 평가할 수 있는 장비들이 개발되어 사용되고 있지만 국내에서는 아직 이러한 다짐평가장비의 사용이 보편화 되어 있지 않다. 이 연구에서는 모형지반에서 진동핸드로울러를 이용하여 다짐을 실시하고 기존 다짐평가 방법인 들밀도시험결과와 새로운 다짐평가장비인 지오게이지(geogauge), 간이지지력측정기(CASPFOL), 동평판재하시험기(LFWD), 동적콘관입시험기(DCP) 결과를 비교 분석하고 시험장비간 상관성 평가를 수행 하였다. 그 결과 상관계수는 $70{\sim}95%$로 대부분 높은 상관성을 보이는 것으로 나타났다.