The use of band drains for ground improvement has been increased throughout the world during the past 15 years. Apart from other ground improvement techniques, the quality of band drains affects greatly the well resistance of drains, discharge capacity and clogginf tests for four drains selected are carried out and quality is examined.

In Resent years, urban tunnels have been more deeply constructed due to the congestion of buried steuctures. In such conditions, the shield method has become one of the popular urban tunnelling method by reason of several characteristics ; safety of construction, mimium environmental damage, and workbility. In tunnelling, the space which is tail-void are created between the ground and the other face of the primary lining. in other to reduce the ground seformation, it is important backfilling in tail-void. In this paper, the result of an experimental investigation undertaken to evaluate the physical and mechanical propeties of grouts composed of various mixtures of backfill materials. And the backfill injection model test was carried out considering the effects of tail-void.

In recent years, Natm has been successfully applied to difficult ground conditions with the use of soil-perservention methods which promote face stability and restrict excessive ground movement. When the tunnle excavation od made through difficult ground like highly weathered rock, the umbrella arch method is often adopted which pre-reinforceas tunnel crown periphery using a stiff shell-shaped structure. The umbrella arch method was originally developed in Itali, and has recently been confirmed its effectiveness in Korea as well. However, no in depth study on the umbrella arch method has been conducted ans as a result no rational analysis/design method is available at present. Therefore this study was undertaken with the aim of identifying the basic reinforcing mechanism and satablishing both qualitative and quantiative relationships between various design parameters and ground movements.

Recently, a more strict regulation has become effective on ground vibration and noise induced by construction activities. Consequently the demand for the most widely used method of installing precast piles, i.e. driven piles, is declining. At the same time the demand for low noise and low vibration piling method increased sharply. Currently there are several different low noise and low vibration methods of installing precast piles, mostly preboring method. However, the actual level of ground vibration and noise of these method of construction has not yet been clearly understood. In this paper, through field measurement, suggestion has been made to meet the requirements of the revised regulation.

일반적으로 일반 및 유해폐기물 매립지에서 진흙층의 기능적 수행목적은 다음과 같다고 할 수 있다. 지표면 유출의 증진을 위하고, 우수의 침투억제 및 폐기물의 표면 노출 시 완충작용, 따라서 최종복토의 붕괴는 이러한 중요 기능을 마비시키고 있다. 본 연구는 추운 날씨상태의 폐기물 매립지 최종복토의 거동을 수행하였으며, 실제로 설계된 세 개의 거대한 실험실 Tank에서 복토에 대한 실험이 시행되었다. 이 거대한 실험장비의 제원은 0.75m x 2.4m와 2.0m 깊이로 되어 있다. Tank안은 시방서적으로 폐기물 매립지가 요구하는 진흙층과 최종복토를 위한 물질로 채워졌다. 그들의 실험결과는 동질/융해에 따른 진흙과 복토층의 붕괴현상은 물리적, 공학적인 측면에 영향을 주는 것으로 나타났다. 본문은 실험에 사용된 복토층의 묘사, 그들의 실험결과들과 실험을 통한 결과분석 및 결론을 설명하고 있다. 실험결과로서는 각 모형들의 우수와 침출수 자료, 온도변화의 배경과 최종복토에서의 Water Balance를 포함하고 있다. 또한 결과로서 시험된 세 개의 모형들은 매립지에서의 동결깊이(29cm~32cm)를 나타내주며 그들 중 하나의 모형은 배수층을 가지고 있어 침출수억제에 효과적이므로 다른 모형보다 복토층으로서 우위에 있다는 것을 지적하고 있다.

Evaluating stiffness of near-surface materials has been one of the critically important tasks in many civil engineering works. It is the main goal of geotechnical characterization. The so-called deflection-response method evaluates the stiffness by measuring stress-strain behavior of the materials caused by static or dynamic load. This method, however, evaluates the overall stiffness and the stiffness variation with depth cannot be obtained. Furthermore, evaluation of a large-area geotechnical site by this method can be time-consuming, expensive, and damaging to many surface points of the site. Wave-propagation method, on the other hand, measures seismic velocities at different depths and stiffness profile (stiffness change with depth) can be obtained from the measured velocity data. The stiffness profile is often expressed by shear-wave (S-wave) velocity change with depth because S-wave velocity is proportional to the shear modulus. that is a direct indicator of stiffiiess. The crosshole and downhole method measures the seismic velocity by placing sources and receivers (geophones) at different depths in a borehole. Requirement of borehole installation makes this method also time-consuming, expensive, and damaging to the sites. Spectral-Analysis-of-Surface-Waves (SASW) method places both source and receivers at the surface, and records horizontally-propagating surface waves. Based upon the theory of surfacewave dispersion, the seismic velocities at different depths are calculated by analyzing the recorded surface-wave data. This method can be nondestructive to the sites. However, because only two receivers are used, the method requires multiple measurements with different field setups and, therefore, the method often becomes time-consuming and labor-intensive. Furthermore. the inclusion of noise wavefields cannot be handled properly, and this may cause the results by this method inaccurate. When multi-channel recording method is employed during the measurement of surface-waves, there are several benefits. First, usually single measurement is enough because multiple number (twelve or more) of receivers are used. Second, noise inclusion can be detected by coherency checking on the multi-channel data and handled properly so that it does not decrease the accuracy of the result. Third, various kinds of multi-channel processing techniques can be applied to f1lter unwanted noise wavefields and also to analyze the surface-wavefields more accurately and efficiently. In this way, the accuracy of the result by the method can be significantly improved. Fourth, the entire system of source, receivers, and recording-processing device can be tied into one unit, and the unit can be pulled by a small vehicle, making the survey speed very fast. In all these senses, multi-channel recording of surface waves is best suited for a routine method for geotechnical characterization in most of civil engineering works.

In tennelling lattice girders have basically the same function as steel arch supports. They serve as elements of temporary lining and in some cases also as part of the permanent lining. Also lattice girders are closely connected with that of the shotcreting lining technique. This paper presents the results of modelling test for analysing shorcrete rebound, shotcreting time and finding void spaces using the aretificial tunnel wall which consist of wood to evaluate the site applicability of lattice girders for tunnel support. Test results indicate that in case of using lattice girders as a tunnel support material, shotcrete rebound, shotcreting time and occurrence of void spaces are relatively reduced comparing to H-beam steel rib. And we can get some informations ths lattice girder has various advantages when we use it as one of tunnel support materials.

한계상태설계법이 지반공학에 도입되었다. 하중과 지지계력수법 그리고 우로코드로 되어있는 본 설계법에서 신뢰성이론을 토대로 한 전자는 북미지역에서, 반통계론적인 후자는 최근에 통합된 유럽연합에서 오래동안 연구 후 채택하였다. 본 논문은 이러한 설계법을 방법론적으로 검토접근하며 다른 선진국의 연구활동을 알아봤으며, 하중과 지지력계수설계법에서 관입말뚝에 대한 지지력계수를 결정하는 합리적인 방법론을 제시하는데 있다.

Some of the ancient earthworks and foundations in china such as the great Wall and Tu-jian-yan Irrigation Head Works as well as the foundations of several ancient bridges and pagodas are introduced in the paper with emphasis on their geotechnical engineering aspects.

지반공학 및 지반환경분야에서 문제의 관건은 표층과 흙의 성질에 대한 정보를 정확히 파악하는 것이다. 표층의 상황은 어느 현장이나 공간적으로 그 성질을 달리하므로 기술자의 경험이나 지구통계학을 이용하여 적절한 현장의 상태를 분석하게 된다. 휴스톤대학에 위치한 미국국립시험현장에서 수행한 28개의 콘관입시험을 통해 얻은 자료를 가지고 지구통계학적분석을 하여 비배수 전단강도의 3차원적 형태를 파악하였다. 본 연구를 통하여 지구통계학의 유용함과 현장의 변화가 상당함을 쉽게 이해하게 된다.

the Effect of steel pipe reinforced multi-step grouting(SPRG) technique to inrove the ground far ahead of the excavation face was investigated by means of numerical analysis. It was found taht the nonlinear 3-D FEM program performed well to evaluate the usefulness of the SPRG technique in soft ground tunnelling, and about 20% of settlement control in this particular case possible. Therefore in urban subway tunnel construction, the New Austirial Tunnelling Method can be satisfactorily applied even in poor ground conditon with aid of the SPRG technique.

The JV method is an epochal civil engineering style that boasts of significant pile driving power through low-vibration works by ideally combining the high pressure water injected from the water jet cutter and the vibrations combining from the vibratory pile driver extractors. As a result, you are ensured stable and safe pile driving and extraction in bedrocks that were previously impossible with conventional machines and methods. The other advantage is its high performance and a low-pollution characteristis that is ensured by suppressing ground vibrations. This is a very important factor since it often becomes an issue upon civil engineering in the city. With the addition of this method. the range of steel pipe pile, steel sheet pile and other steel pile use has been drastically expanded. Other advantages of this method incldes accurate works, shortening of the construction period and improved work performance. Since the minimun amount of high pressure water is used to drill the ground, it not only loosens the ground, but also cuts the ground at the tip of the pile to improve driving works.