Research On Physical Properties And Relationship Between Strain And Stress Of Peat & Peaty Soil In Yunnan

Distribution of peat & peaty soils in china is not harmonious. Five accumulated regions of peat & peaty soils are distributed especially: Modern accumulated regions of peat & peaty soils at Dongbei highlands; Modern accumulated regions of peat & peaty soils at middle and lower reaches of Changjiang River; The accumulated regions of peat & peaty soils at Yunnan and Guizhou plateau; The accumulated regions of peat & peaty soils at Leizhou peninsulas; Seen from the reserves of peat &peaty soils in every province, every city and autonomous regions. The reserves of peat & peaty soils in Sichuan are the most abundant. That of peat & peaty soils in Yunnan are secondary, and that of peat & peaty soils in Gansu, Jiangsu, Xizang, Heilongjiang, Anhui, Jilin, Neimenggu and Xinjiang go beyond a hundred million dun.As a special soil, peat & peaty soils in Yunnan contain some properties with bigger pore ratio, higher water content, higher compression, higher organic content, etc. peat & peaty soils in Yunnan are exceptional soft soils, therefore, research on physical properties and model parameters of them is necessary for practical projects.In the present paper, physical properties tests and a series of laboratory traxial experiments were conducted, and it was found that the relationship between strain and stress. Model parameter K_t is based on Domaschuk-Valliappan model, and model parameter G_t is based on Duncan-Chang model.I present here the results of study that the value of natural weight ranged from 9. 5 kN/m^-3 to 12 kN/m^-3, and the value of pore ratio ranged from 2. 5 to 8. 5, and the value of water content ranged from 100% to 600%, and the value of organic content ranged from 10% to 65%, and the value ofcompressive coefficient ranged from 1. 5MPa^-1 to 15 MPa--1. However, themodel parameters were obtained through analysis on experimental results: The results also showed a parameter e_ao of 6. 61 and a parameter λ of 0.489;the value of parameter K ranged from 50 to 100, and the value of parameter n ranged from 0. 4 to 0. 75, and the value of parameter R_f ranged from 0.85to 0.95. and the value of the internal friction angle ranged from 10° to 25°, and the value of cohesiveness ranged from 15kPa to 30kPa. All the data and parameters provide consultative basis for practical projects.Processing methods of peat soil ground are various, which will be chosen due to engineering geological condition, time limit, cost, and environmental requirement, etc. constant processing methods are as the follows: Processing method of the upper ground layer, Unload method, Replacing soil method, Surcharge precompression method, Consolidation method of using sand well, Compaction sand pile method, Deep mixing method, Pile foundation method. This paper united practical project, according to laboratory experiments and testing ground, the qualities of pile were examined. Peat & peaty soils in Yunnan through ground treatment meet design requirement and effect is very evident.