Ningbo is located in the southeast coast plain. There are thick, soft soil deposits lying in the sub-ground, which challenges the construction of urban rail transit in this area. A project of Ningbo Rail Transit Line 1 and the soil conditions for the construction site are firstly presented. Then, the excavation engineering designs for the project are summarized from four aspects: the design of building envelope, vertical and horizontal layout of supporting system, underground water dewatering and ground treatment. Simultaneously, the problems occurred in the design are also described. Lastly, the experiences gained from the project are summed up, so as to guide the further subway construction in the area and also provide a reference for the construction of similar project.

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In congested urban area it is common to do excavation several meters lower than ground surface to have sufficient space for car parking and electromechanical facilities. Excavation is one of hazardous tasks in the context of civil engineering activities. Geotechnical assessments coupled with engineering geology explorations play important role in reducing hazards associated with excavation. In these excavation works, especially in megacities, concentration on engineering geology aspects of the sites is usually at least or ignored. That is, geological features of the site in addition to the geotechnical properties have to be studied. On the basis of observations, between different case studies, and in one of excavations, this paper presents documented problems encountered governing by presence of a large fault zone. Of these problems are uncontrolled deformation in some parts of the retaining wall and its consequent to damage neighboring buildings, local uprising water table and its effect on the internal and external slope stability. This case study has been done on hard soils that faulting has generated a wide crushed zone with tight fault planes. In this case, it is advised to consider these weak planes in modeling when engineers want to evaluate slope stability safety factor by limit equilibrium analysis and/or calculation of deformation due to excavation by finite element method. These collaborations have to be continued along the excavation implementation because, in these cases, supports with sufficient capacity with the slot excavation (sequential excavation dictated by soil conditions) are needed. That is, two disciplines of geotechnical engineering and engineering geology should support together properly. Therefore, I selected one of problematic project in that there was not such reconciliation between geotechnical and geological data thereby it experienced damage from these defects.

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In snowy cold regions, embankments constructed in winter may have settlement and collapse of slopes in the thawing season in early spring. One of the reasons may be unavoidable suspension of the work sequence for constructing an embankment during a cold winter. Accordingly, assuming such work condition, a test construction was conducted in the winter season. For the constructed embankment, its inside temperatures and strength were measured. Also, after the embankment melted it was cut open and the density and water content were measured. As a result, it was found that. The results of this study can be summarized as follows: 1) even in a 30cm high embankment, frost and moisture movement occur, 2) a frozen embankment is strong but a non-frozen one is not strong, 3) depending on the embankment construction method, layered frost remains and the number of layers increases with the increase of construction days, 4) when the embankment freezes the density decrease, 5) that the laying of insulating material is very effective a controlling freezing.

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Embankment is one of the most important soil structures that correspond with the diversity of performance. The typical regulation for embankment is the degree of compaction at the top of embankment. In order to properly prevent embankment failures due to natural disasters improvements of quality and function of embankments are considered. In this paper, firstly, improvements of compaction effect are investigated by applying a general compaction method to the test embankment. Secondly, in order to develop a new system for evaluating the degree of compaction on the embankment slope a non-destructive testing was performed in the laboratory and site. Furthermore, the relationship between the degree of compaction and ground stiffness obtained from non-destructive testing were investigated in detail. An effective procedure for evaluating the quality of the embankment slope was proposed.

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The Load Resistance Factor Design (LRFD) was introduced in Korea about a decade ago. However, the resistance factors suggested by AASHTO (2007, 2010) represent the characteristics of bedrocks in the US that may differ from those in Korea. There is also a general belief that the calculated probabilities of failure from conventional reliability analyses are not realistic because of the conservative bias used when predicting resistance and tails of probability distributions for load and resistance. The existence of a lower bound of resistance affects the reliability and resistance factors even though the lower bound of resistance is small. Thus, it is important to determine accurate resistance factors for drilled shafts based on reliable load test results and to calibrate the resistance factors considering lower-bound resistance. In this paper, an accurate resistance factor for drilled shafts was determined based on 13 sets of drilled shaft bi-directional load test data with strain gauges. Using a new log-normal distribution with lower bound of resistance, reliability analysis and resistance factor was performed using the advanced first order second moment (AFOSM) method. The target reliability indices were determined as 2.5, 3.0, and 3.5. For the target reliability index of 3.0 (AASHTO recommended value), the resistance factors were determined in the range of 0.13-0.32 for shaft resistance, 0.19-0.29 for base resistance. The lower bounds of resistance for each resistance (shaft and base) were determined, to be applied in the various bearing capacity equations, based on the Hoek-Brown failure criteria (2002) and the downgraded GSI values. Considering the lower-bound resistance, resistance factors were increased by up to 8% for the shaft resistance factor and 13% for the base resistance factor.

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Tailings are one of the primary solid wastes of mining industry. They are made of fine-grained particles of the parent rock from which the ore is extracted by crushing, grinding, and other milling processes. Furthermore, volumetrically, tailings impoundments are among the largest structures created by human kind. The safety of the tailing reservoir is one of the major concerns. The characteristics of tailings are a result of the composition of the parent rock and the method of ore processing. In this paper, the two types of tailings from an iron mine in South China were systematically investigated in terms of their mechanical characteristics including the physical features and dynamic response. The deformation of tailing reservoir in design was evaluated considering the earthquake load. This study provides a scientific basis for optimal design and safe operation of the future tailings storage facility.

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Around major cities, the housing development called the bedroom town was developed, and the residential land development that downplayed safety was carried out with green destruction by a chaotic creation plan. In the residential areas, developed in the suburbs of Sendai around 1955-1965, a lot of houses suffered from geotechnical damage during the Great East Japan Earthquake. In this study, we made an embankment preparation map by comparing a digital map made from an old planning map and a current digital elevation map. Furthermore, we developed a map database of construction sites for preventative measure and a map database of applications for the dismantling of damaged property for locations under consideration for public development that were damaged by the Great East Japan Earthquake. We reviewed and compared prices of the inheritance tax street value by an embankment preparation map and a database of applications for the dismantling damaged property. It is reasonable to make different evaluations between residential lands that need ground improvement and residential lands that don't need ground improvement because they have been evaluated in the same way whether damage or not. We considered residential land evaluation formulae (street value evaluation formulae) that evaluates value of residential land according to ground vulnerability measurements. In conjunction with proposing the consideration of ground structural characteristic correction to residential land price evaluation, we calculated a ground structural characteristic correction.

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