ABSTRACT
Strongly expansive soft rocks, distributing widely in China, result in great damage to engineering construction, one important reason of which is the construction begins without making clear its deformation mechanism. Expansive soft rock’s problems are one of the most complicated study topics in the fields of Engineering Geology and Rock Mechanics all over the world. China is one of the countries distributing expansive soft rocks widely which outcrop from Heilongjiang and Inner Mongolia in the north to Sichuan and Yunnan in the south. When Jilin-Huichun speedway was been constructing in Yanji Basin, slope failures happened, such as the No. 01 section of Yanji-Tumen and Maoershan landslide, which brought very bad effect on construction. The rock and soil belongs to strongly expansive soft rocks for its disintegration and weathering was strong with plentiful microfissures. So its deformation mechanism is molecules and microfissures expansive mechanism.
