Reinforcement for Upgrading Earth Structures Using Geocomposites under Cyclic Loading

本研究的目的是探索一种加固方法，升级的土结构在交通，海浪和地震引起的循环荷载下，使用土工合成材料，由两种或三种不同的土工合成材料组合而成。本研究的关键词是“混杂”和“夹层”，主要包括以下两个方面：（1）研究中使用的材料是一种混杂材料，即非编织土工合成材料与类似夹层的编织土工合成材料相结合;（2）在土工合成材料的两侧、上方和下方放置砂垫。这种类型可以称为混合夹层土结构。为了实现具有混合土工合成材料的混合土结构的优点，进行了模型试验和数值分析。研究结果表明：（1）土工合成材料与砂垫层之间形成的夹层结构有利于软土地基的加固，其加固效果优于土工合成材料 关于我们 2）砂垫层与土工合成材料的夹层结构相结合，可以提高土工合成材料的渗透性和透水性。编织土工合成材料夹在编织土工合成材料中间的土工复合材料最适合实现这一目的。3）夹层结构的优势体现在两个方面：一是提高了路堤的稳定性，减小了路堤的变形和沉降。编制了考虑土工合成材料约束对夹层结构路堤变形和稳定性影响的有限元计算程序。本文提出了一种新的加固方法，即在夹层结构中将水泥砂浆注入垫层中，作为加固地基和土结构的一种有前途的混合体系。特别是，该系统可以有效地增加稳定性并减少交通海浪和地震引起的循环载荷下的沉降。6）无论是使用土工复合材料还是将无纺土工合成材料与注入水泥砂浆相结合，都可以在遭受海浪作用的沿海地区产生稳定的加固护岸。少

The present study aims at exploring a reinforcing method for upgrading earth structures under cyclic loading induced by traffic, ocean waves and earthquakes by using geocomposites which are manufactured by combining with two or three different kinds of geosynthetics. The keyword in this study is "Hybrid" and "Sandwich" which contains the following two aspects :I) The material used in the study is a hybridized one in which the unwoven geosyntheitc is combined with the woven geosynthetic similar to the sandwich.ii) Sand mat is placed at the both sides, above and beneath the geocomposite. This type can be called a hybrid-sandwich earth structure., In order to accomplish the advantageous aspects of the hybrid earth structure with the hybrid geosynthetic, model tests and numerical analysis were carried out. The following main findings were derived from the present study :1) Sandwiched structures formed by sand mat placement in-between geosynthetics contribute to improvement of soft soils mo … More re markedly than in the case with sand mat only without geosynthetic reinforcement.2) Sand mat placement combined with geosynthetics as a sandwich structure gives rise to improvement of permeability and transmssibity of geosynthetics. The geocomposite in which the woven geosynthetic is sandwiched by the woven geosynthetic in-getween is most suitable for accomplishing this purpose.3) Advantages of sandwiched structures are recognized in the two aspects : the one is increase of stability of embankment and decrease in deformation and settlements of embankment.4) The finite element computer code is formulated to consider the effect of confinement due to geosynthetics into deformation and stability of embankment with the sandwich structure.5) Anew method combined by injecting cement mortar into send mat in the sandwich structure is suggested as a promising hybrid system for upgrading foundations and earth structures. In particular, this system is effective to increase stability and reduce settlements under cyclic loading induced by traffic ocean waves and earthquakes.6) Either the use of geocomposite or the combination of non-woven geosynthetic with injection of cement mortar gives rise to stable reinforced revetments at the coastal area subjected to ocean wave actions. Less