鉛直群ぐいの荷重〜沈下挙動に関する研究 : その 3・ネガティブフリクション現象について

抄録

The behavior of single piles or pile groups due to negative skin frictions induced by ground settlements are studied in this paper. Fundamental equations were already shown in serial report Part I by authors. Authors tried to clarify that this theory is applicable to site phenomena observed by using various efficient apparatus. Some important points on analysis about negative skin friction phenomena should be as follows, 1) estimation of skin frictional strength and their distributions 2) ground settlement quantity and their distributions 3) rigidity of ground explained by appropriate conception of soil model 4) stratified situations of ground 5) scales, compressibility and number of piles 6) interaction between piles and ground. In this paper facters 3), 5), 6) mensioned above or partially 4) are mainly considered. Another facters are treated mainly as known quantities from observed data. In this report three observed data (EX. 1, 2, 3) are picked up as follows. These are all steel pipe piles driven into about 40 meters clayey deposit. EX. 1 three single piles (one 31 meters and two 43 meters long piles) EX. 2 one single pile and 2 or 5 pile groups at 2.5 diameters spacing about 40 meters long EX. 3 one single pile and 38 pile groups at about 2 diameters spacing about 40 meters long Relations between observed data and calculated results about axial force distributions, neutral points, pile top settlements and their pile group effects are discussed. In conclution authors consider that our theory fairly applicable to site phenomena.