地震引起的永久变形是评价地震时地基和土工结构物性能的一个重要依据。早在六十年代,Newmark就曾指出,用地震引起的永久变形来评价土坝的抗震性能比滑动安全系数更合适。按地震时的性能土可分为两大类。第一类土,在地震时孔隙水压力没有明显地升高或抗剪强度不产生明显的降低,这类土包括干砂、压实的粘土、密实的饱和砂土等。第二类土,在地震时孔隙水压力会明显地升 Earthquake-induced permanent deformation is an important basis for evaluating the performance of foundations and geotechnical structures during earthquakes. As early as the 1960s, Newmark pointed out that it is more appropriate to evaluate the earthquake resistance of earth dams than the sliding safety factor by using permanent deformation caused by earthquakes. Performance by earthquake can be divided into two categories. In the first soil, the pore water pressure did not increase significantly or the shear strength did not decrease significantly during the earthquake. This type of soil included dry sand, compacted clay, and dense saturated sand. In the second soil, the pore water pressure will rise significantly during the earthquake