Study On The Triaxial Compression Experiment Of The Metamorphic Soft Rock Filler In Shi-Tian Expressway, Western Section Of AnKang

In the construction process of highway, it produces abundant of metamorphic rocks in Qinling Mountains. If we discard these metamorphic rocks, it will not only bring damages to our surrounding eco-environment, but also add cost to the highway construction, which is against with the new harmonious concept of reducing cost, protecting ecosystems, and fitting into the ambient environment under construction. However, the minable metamorphic rocks have characterized by weathering degree strong and rock strength low. Moreover, the disadvantages of its easily deformable packing properties and low strength when it met water limits application into the highway subgrade construction. For this reason,this paper, relying on the Ankang west-middle section of express way from Shiyan to Tianshui, conducts a study to the stress and strain of metamorphic rock filler by the abrasive disc electron experimentation, the point loading test, the crumbling expansion test, the shaking table test and the large scale triaxial test. The main research results are as follows:1. The paper studies the mineral composition of metamorphic rock and names the rocks by analysis the abrasive disc electron experimentation. The paper determines metamorphic rocks are the metamorphic soft rock by the experiment of point loading test to assay compressive strength of rock sample. The paper concludes that metamorphic rocks are less likely to expand through the crumbling expansion test. Similarly, the paper reaches a conclusion that metamorphic rocks belong to the higher Durability rock through the shaking table test.2. The thesis researches the mechanical characteristics of metamorphic rocks as well as the affect to its intensity parameter in different density by the large scale triaxial test. Experiments show that with the increase of confining pressure, stress-strain relationship tends to softening type, the softening degree mainly depends on pressure size; when it is at lower pressure, metamorphic rocks will show bulk shrinkage at first, then with the enlargement of Axial strain, it will change from bulk shrinkage to bulking, then with the increase of confining pressure, dilatant deformation gradually will decrease, at the same time transit to all the shrinkage, while volume shrinkage ratio gradually inclines to stabilize; water plays an important effect on shear behavior of metamorphic rocks, which largely presents the drop of shear strength parameters.3. According to the phenomenon that metamorphic rocks easily produce the higher particle breaking in lower stress levels, and owing to the influence of particle breaking to the material of dilatant properties and shear strength, therefore, the dissertation analyzes the particle breaking of metamorphic rocks under the action of shearing.