The safety factor method is used in the present designs of siol structures and foundations. The values of safety factor in those design are given through many engineer's experiences. The variations of external force such as wind load and soil strengths and the accuracy of design formulation must be covered with the fafety factors. Reliability-based design related to soil structure has recently developed as a new design method that can evaluate quantitatively those uncertainties based on theories of probability and statistics. This method receives much attention as a more reasonable design. However, it is difficult to use reliability-based design to the practicaldesigns. This is because many past researches aimed at the establishment of the methodology in general. Therefore, the purpose of the present study is to develope the practical reliability-based design method taking account of the peculiarity in each design.The subject of the present study is the problems related to embankment on saturated clay 1ayer and slope which consists of saturated clay, cut slope which consists of partially saturated soils and caisson type pile for transmission line tower. These structures belong to "lifeline" in the broad sence. The mechanical properties of them are discussed on the basis of the proto-type experiments and laboratory tests. The accurate slope stability analysis and the simplified bearing capacity formula for design are proposed. These results are incorporated into the developed practical reliability-baseddesign method.This thesis consists of the following chapters;Chapter 1 : The aim of this thesis is presented and the past researches related to this thesis are summarized.Chapter 2 : The proto-type and model tests, and actual case records of slope failure during raifall are shown to simplify the mechanism of these strutures in later chapters.Chapter 3 : The statistical properties of soil, rock parameters and wind load are summerized from the results of past investigations and new soil explorations in the present study.Chapter 4 : The procedures of reliability-based design related to embankment on saturated clay layer and slope which consists saturated clay are described in detail. In the former the construction methods of changing slope gradient, counterweight fill, sand compaction pile and sand drain can be taken account of easily to apply to the present design. In the latter new stability charts present to obtain the accurate failure mode of slope. These results of optimizations are compared with the results of the conventional safety factor method.Chapter 5 : The procedure of reliability-based design of slope which consists of partially saturated soils is discrived. As well as Chapter 4, specifications in safety factor method are examined by the results of the optimizations. The new method for predicting slope failure during rainfall are also developed based on acutual case records of cut slopes along Chuo Expressway. The method can evaluate not only both the reduction of soil strength along slip surface and the increase of self weight of slope due to seepage but also some other factors such as rainfall intensity, antecedent precipitation, vegetation, slope protection, weathering and spring water.Chapter 6 : The simplified bearing capacity formula of caisson type pile for transmission line tower are established from the results of proto-type tests shown in Chapter 2. They are incorporated into the reliability-based design. The developed design method in this chapter can evaluate not only the probability of failure but also the probability which the displacement of foundation will exceed the allowable displacement.Chapter 7 : The conclusions in the thesis are summarized.
名古屋大学博士学位論文 学位の種類 : 工学博士(論文) 学位授与年月日 : 平成1年2月7日