土力学问答题（Soil mechanics essay questions）.docVIP

土力学问答题（Soil mechanics essay questions） Short-answer questions What is the difference between the compression properties and the strength characteristics of normal consolidation clay and superconsolidation clay? A: the maximum effective stress in the history of soil is called preconsolidation stress, which is expressed by PC. The ratio of the pre-consolidation stress and the existing stress Po is called overconsolidation ratio OCR, and the soil is overconsolidation for natural soil, OCR 1. When OCR = 1, it is normally consolidated. OCR = 1 and the existing effective stress p 0 is less than the existing consolidation stress p0, which is unconsolidated soil The compression characteristic difference: when the pressure increase phase, the normal consolidation of the soil is larger than the overconsolidation soil. The difference of strength characteristics: the superconsolidation soil is stronger than normal consolidation soil. Shear properties: because the unconsolidated soil also belongs to normal consolidation soil, they have the same shear shape, that is, shear shrinkage and positive pore water stress can occur when shearing. Over-consolidated soils are divided into strong over-consolidated soils and the weak over-consolidated soils, weak over-consolidated soils in shear, as well as the normal consolidation soil shear shrinkage volume, pore pressure is, but the pore water pressure is smaller than normal consolidation soil; The shear swelling effect and negative pore water stress can be generated during the shear process. 2. Describe the factors affecting soil compaction? A: the influence factors of soil compaction mainly include water content, compaction function, type and grade of soil and coarse grain content. The influence of water content of cohesive soil, main show is when moisture content is low, under the same compaction function of dry density is low, with the increase of water content, dry density obtained by gradually increase; When the water content is rea