정지토압계수 측정에 관한 연구 1

송무효(MU-HYO SONG) 한국해양공학회 2001 韓國海洋工學會誌 Vol.15 No.4

It is very important to determine the coefficient of earth pressure at rest accurately in order to estimate the behavior of soil structure. For estimation of K0-value depending upon the stress history of dry sand, a new type of K0-oedeometer apparatus is devised, and the horizontal earth pressure is accurately measured. For this study, 2 types of one-cyclic K0-loading/unloading models have been studied experimentally using four relative densities of the sand. The results obtained in this test are as follows : Kon' the coefficient of earth pressure at - rest for virgin loading is a function of the angle of internal friction φ' of the sand and is determined as Kon=1 - 0.914 sin φ', Kou' the coefficient of earth pressure at rest for virgin unloading is a function of Kon and over consolidation ratio(OCR), and is determined as Kou=Kon (OCR)<SUP>a</SUP>. The exponent a, increases as the relative density increases. Kor' the coefficient of earth pressure at rest for virgin reloading decreases in hyperbola type as the vertical stress, σv', increases. And, the stress path at virgin reloading leads to the maximum prestress point, independent upon the value of the minimum unloading stress. The gradient oj this curve, mr, increases as OCR increases.

정지토압계수의 측정장치 개발에 관한 연구

송무효(Mu-Hyo Song) 한국해양공학회 1999 韓國海洋工學會誌 Vol.13 No.2

For exisiting K0-oedometer, the lateral wall of the ring is cut thinly to make space and by filling the space with water or mercury to keep the balance to the lateral pressure of a specimen, the pressure of the fluid is checked for the pressure of the specimen.<br/> But the devices to keep the balance to the lateral pressure of a specimen are complicated, difficult to manufacture and expensive.<br/> As newly developed K0-oedometer is equipped with the load cell which can resist higher pressure than the lateral pressure of the specimen, there is nearly no deformation due to the lateral pressure of the specimen.<br/> And the measuring is cheap and easy as there are fewer accessories.

K_o-재하/제하에 의한 건조모래의 거동 (II) : 다주기 시험

정성교(Sung Gyo Chung),송무효(Mu Hyo Song),정진교(Chin Gyo Chung),남선우(Sun Woo Nam) 한국지반공학회 1995 지반 : 한국지반공학회지 Vol.11 No.1

천해역 점성토 지반에 적합한 오탁방지막 기초 앵커

권기철(GI-CHUL KWEON),홍남식(NAM-SEEG HONG),송무효(MU-HYO SONG),최창규(CHANG-GYU CHOI) 한국해양공학회 2003 韓國海洋工學會誌 Vol.17 No.3

The Navy has tested the holding capacity of many kinds of anchors in order to propose the design chart for the holding capacity of drag-embedment anchors. The design chart is only applicable up to the cable bottom angle 6° when load is raised to the ultimate weight. However, the anchor experiences a significant uplift force when the angle is above 6° in shallow seas. In this paper, the procedure for the estimation of the holding capacity of anchors in mud is proposed. Drag-embedment anchors do not function well when there is a significant uplift component of load in soft seafloor materials, such as mud. Under these loading and seafloor conditions, gravity anchors seems to be more efficient. However, they are too heavy for their holding capacity. Therefore, suction pile (hollow concrete block) is more beneficial to the foundation of silt protector in shallow sea with mud seafloor materials.

모래의 다주기 Ko - 재하/제하에 대한 실험적 연구

송무효 東義大學校産業技術開發硏究所 1992 産業技術硏究誌 Vol.6 No.-

In estimation of the lateral earth pressure at-rest of an under-ground rigid structure, the coefficient of earth pressure at-rest, ?? os determined mainly by the angle of internal friction of the soil and also is well-known influenced considerably by the stress history of the soil it. In this study the influence on the stress history of the dry sand is deeply examined and hysteretic ??-model considering the above two factors is suggested. For this, total 9 types of one-cyclic and multi-cyclic models under ?? condition have been studied experimentally. For this study ??-tester which has an oedometer ring on the inner wall of which load cells are attached is newly devised and the horizontal earth pressure is accurately measured. There have been several relating studies on the one-cyclic ??-test. By these studies, for virgin loading K?=f(Φ')and for virgin unloading ?? =??(OCR)?? are suggested. And for virgin reloading ??'-??' relationship is expressed linearly and the reloading coefficient defined by the gradiant of the straight line, ?? is expressed by the function of OCR and Φ'. The results of this study are analyzed by and compared with those of the relating studies. As there have been few studies on the multi-cyclic K?-test the writer tried to determine the extending relation considering cyclic number on the functional formula obtained in one-cyclic test.

지지력 실험을 통한 지반강도정수의 추정에 관한 연구

송무효,홍석우 동의대학교 산업기술개발연구소 2001 産業技術硏究誌 Vol.15 No.-

기존의 얕은 기초의 지지력 이론은 지반이 동시파괴(전반전단파괴)를 일으킨다는 강소성을전제로 하고 있으며, 이론식 속의 지지력 계수(Nc, Nr, Nq)는 단지 지반의 내부마찰각(φ)만의 함수로 표현되어져 있다. 따라서 파괴의 진행성, 또는 재하폭에 따른 영향이 명확히 고려되어져 있지 않다. 이에 본 논문에서는 주문진사를 이용하여 중간·조밀의 모래지반을 성형하곡 재하폭(B)을 변화시켜 실험하였다. 실험결과로부터 조밀한 모래지반에서도 진행성 파괴(Progressive Failure)와 크기 효과(Scale Effect)가 나타남을 알 수 있었다. 본 연구에서는 이들 영향을 고려하기 위하여 이론과 실험에 의한 Nr의 비를 지지력계수비(Rr)라고 정의하였고, 모래지반의 내부마찰각을 추정하는 방법을 제안하였다. The theoretical bearing capacity equation of shallow foundation has been proposed under the state of a general shear failure and by using the rigid plastic theory. The bearing capacity factors(Nc, Nr, Nq) of theoretical equation are also decided by internal friction angle(φ) only of ground. Therefore, the effect of progressive failure and loading width are not considered in it. In this paper, the laboratory model tests are performed for medium and dense Joomunjin standard sand with variation of width of loading plate. From test results, the effect of progressive failure and loading width are analyzed. And, the ratio of bearing capacity factor(Rr) is defined, which can be calculated using theoretical value of Nr and experimental value(Nr') of Nr. By using ratio of bearing capacity factor(Rr), the internal friction angle of sand ground can be obtained from test results of bearing capacity.

건조모래의 상대밀도와 마찰력과의 관계에 대한 연구

송무효 東義大學校産業技術開發硏究所 1998 産業技術硏究誌 Vol.12 No.-

An experiment to determine the relationship between the relative density and the friction of dry sand is done in this paper. The specimen is the Joo-Mun-Jin sand. The relative density and friction force are determined by the air-pluviation method. The result is when the relative density is 44%, 65%, 86% respectively, the of friction force is 6.85kg, 6.93kg, 7.00kg the coefficient of friction is 0.556, 0.563, 0.569 and the friction angle is 29°60′, 29°23′, 29°38′ respectively. And the friction angle is the maximum when the falling height is 90cm.

매설관에 작용하는 토압의 측정에 관한 실험적 연구

宋武孝 東義大學校産業技術開發硏究所 1990 産業技術硏究誌 Vol.4 No.-

A pipeline is buried in or laid on the ground to transport liquid or gas. In this paper the vertical earth pressure which the refilled soil carries to a buried pipeline is obtained by a experimental method and compared with those by Fluhling's and Marston's formula. Here the thesis is restricted to sand. But it is future thesis to put the followings into consideration, the sort of soils, the extent of compaction, the influence of underground water, the change of temperature, the differential settlement, the overload and the earthquake.

모래의 다주기 Kㅇ-재하/제하에 대한 실험적 연구

송무효,정진교 東亞大學校 海洋資源硏究所 1992 硏究論文集 Vol.5 No.1

In the estimation of the lateral earth pressure at-rest of an under-ground rigid structure, K. the coefficient of earth pressure at-rest, is determined mainly by the angle of internal friction of the soil and also it is well-known that Ko is influenced considerably by the stress history of the soil. In this study the influence on the stress history of the dry sand is deeply examined and hysteretic Ko-model considering the above two factors is suggested. For this, total 9 types(of one-cyclic and multi-cyclic models under Ko condition have been studied experimentally.) For this study K.-tester which has an oedometer ring on the inner wall of which load cells are attached is newly devised and the horizontal earth pressure is accurately measured. There have been several related studies on the one-cyclic Kotest. By these studies, for virgin loading Kon=f(Φ') and for virgin unloading, Kon(OCR)α are suggested. And for virgin reloading σh'-σv' relationship is expressed linearly and the reloading coefficient defined by the gradiant of the straight line, mr is expressed by the function of OCR and Φ. The results of this study are analyzed by and compared with those of the related studies. As there have been few studies on the multi-cyclic Ko-test, the writer tried to determine the extending relation considering cyclic number on the functional formula obtained in one-cyclic test.

액성한계측정방법에 관한 실험적 연구

박종호,송무효 東義大學校 産業技術開發硏究所 1997 産業技術硏究誌 Vol.11 No.-

For the determination of the liquid limit , there are the conventional dynamic test and the fall-cone static test. In this paper, the above two tests are compared and the results is followings; the liquid limit for a specimen by the dynamic test is 32.2% and that for the same specimen by the static test in 31.9%, the difference is only 0.3 %, so the static test is recommended for the reason that the static test is easy to do, comparatively near to the natural condition and the difference of the results of the two tests is very little.