| As national infrastructure construction to speed up the rock and soil engineeringis developing rapidly, the domestic study on soft rocks have made a lot ofachievements, and to solve many engineering problems. But because of the intrinsiccomplexity of rock, even the same type of rock has the very big difference. Tuff is aspecial kind of soft rock, especially the tuff engineering problems in recent yearsemerge in an endless stream, so many scholars have conducted some pro perties, buthas not found a suitable solution.This paper is taking Yunnan Lancang as an example to study ore tuff. Through theexperiment to understand Lancang ore tuff of the physical and chemical properties,mechanical properties, engineering properties, hydraulic characteristics, is the focus oftuff water characteristics of expansion and disintegration. We hope to be able to tuff todo a thorough, comprehensive understanding, for the project to provide a certainreference.According to the results of a series of experimental study found:1ã€According to the analysis of Lancang ore tuff, aware of the tuff containing clayminerals and not mixed illite / montmorillonite, but contains only a singlemontmorillonite. Crystal tuff and montmorillonite in before has very obvious changes,showed a tuff macro volume expansion of the inner reason.2ã€Combined with the free swelling test and X ray diffraction test analysis, drawtuff natural free expansion deformation of 47.75%, whereas montmorillonite crystalplane spacing changes in volume35.07%. The instructions cause the volume expansionof the intrinsic reason besides tuff lattice expansion also influence factors.3ã€Through the analysis of mineral composition, found in the tuff water-swellabledisintegration process, the presence of clay minerals occur secondary to change,formed the assemble body of clay minerals. A chemical element substitution effect,leading to a charge imbalance, which is the internal cause of swelling force.4ã€In unconfined conditions have expansion load test, initial moisture con tent, theaxial expansion ratio and axial expansion stress of one-to-one linear relationship existsbetween. And Lancang ore tuff expansion rate is very large, but the expansion stress issmall.5ã€According to the experimental research on disintegration of display, Lancang ore tuff easy disintegration, weathering ability extreme difference, in dry and wetcondition is very unstable disintegration. Tuff in waterlogged before 1H isdisintegrating the most intense, the most rapid, after 6h almost completedisintegration.6ã€According to the liquid limit and plastic limit of mudstone, mudstone tuffdisintegration for silty clay. |
