The Physical And Mechanical Properties. Kunming Chenggong New Area Of ​​red Clay Research

The reason why red clay is different from general clays is its special physical and mechanical properties. With the rapid development of economy, engineering constructions on red clay are increasing day by day, study on red clay is more and more deeply which has made a serise of achievements. Chenggong new city is on the eastern edge of Kunming basin, south-central Kangdian diamond activities fault block which is surrounded by Xiaojiang active fault belt and Pudu river-western hills fault belt, the intersection part of Kangdian axis and eastern Yunnan fold belt. This area is widely coverde by Quaternary system, only small part of places can see bedrock.The mother rock of red clay in Chenggong new city is carbonatite. Under the dissolution and physical and chemical weathering, the residual products sedimentate in lower areas after being moved by water which take shape to modern red clay by a series of complex interactions like later laterization and can be named secondary red clay by alluviation or alluvial-proluvial. Geographic and geomorphic play a controlling role on red clay's distribution. Red clay is always concentrating distribution at negative relief of karst landform, such as flat denudation-leveling terrace and undulate karstic basin. In the early time of red clay's formation,chemical constitution of the residual products is similar to its mother rock's,but great changes have taken place on conten. The ratio of Si/Al/Fe has been increased while Ca/Mg's has been decreased which is high-level in mother rock, Calcium and Magnesium oxide in morden red clay is less than3%. Red clay is allmost composed by undissolved things which are mainly composed by three major part:quartz, iron-bearing mineral and clay mineral,that is different from the residual products. The special engineering geological properties of red clay are due to its physico-mechanical properties.On the base of collecting geotechnical engineering date, after analysing physical and mechanical index of red clay,we know that the red clay in Chenggong new city has these characteristics:low swelling property, fissured, upper layers are rigid and the lower layers are weak, high water content,large void ratio,low density,high liquid limit and plastic limit. Red clay also shows low compactibility and high shear strength and bearing capacity in geotechnical engineering. For further studying on the correlativity of the several red clay's physical-mechanical indexes, scatterplot and SPSS are applied to contrast the correlation analysis, the conclusion is are:(1) Void ratio is the determinant of SPT N63.5, the minor factors are water content, liqiud limit and force density.(2) Probe resistance has correlation with void ratio and water content, but the correlation coefficients is neither high and the relationship curve is not reliable. We can temporarily think that probe resistance is the comprehensive effect of every factor.(3) There is poor correlation between modulus of compressibility Esl-1and each physical index so that Esl-1is affected by each physical index.(4) The correlation between frictional resistance around pile and void ratio is single related curve, as void ratio bigger, the former smaller.(5) There exist certain correlations between angle of internal friction and liquidity index, but the coefficient of regression is low and the regression curve's credibility is not high, so that there is no statistically significant linear relationship between angle of internal friction and every index in this paper.