| With the support of Zhang-sang highway which is going to be built, this paper studies on the main engineering properties of reinforced badly weathered soft rock granular soil embankment fillings. Physical and mechanics tests are conducted to study the physical mechanics properties of badly weathered soft rock fillings. The large-scale consolidated-drained and unconsolidated-undrained triaxial tests are carried out on reinforced soft rock granular soil fillings. Constructing technology on geosynthetic badly weathered soft rock embankment are studied by field tests. Based on experimental data, Finite difference method are used to analyze deformation and mechanical behavior of high filled embankment under dead weight in layer filling process with considering reinforcement and rain penetration. Main achievements are concluded as follows:1. The microstructure and composition of badly weathered soft rock fillings are researched by means of SEM, x-ray diffraction and chemical analysis. The natural collapsing process of soft rocks at the atmosphere is simulated through tests of cyclic watering, blowing and sunning, and the grading of soft rock crumbling pellets is also investigated. At the same time, compaction property, water-stable ability and mechanical characteristics for road are also studied. The engineering properties of badly weathered soft rock fillings are discussed from various aspects.2. In order to study the deformation properties and geotextile reinforcement effect of the geotextile soft rock granular soil fillings, the large scale triaxial tests were carried out. The tests showed the hardening strain in deformation properties of geotextile-soil samples. There exists puny geotextile reinforcement effect while axial strain is less than 1%, and the geotextile reinforcement effect showed more clearly with the increase of axial strain. The pore water pressure of geotextile-soil samples is higher than that of pure granular soil samples, and the pore water pressure of geotextile-soil increases with the geotextile layers. The geotextile reinforced effect coefficients were lager than 1.0, with 1.09～1.21 for one layer geotextile,1.30～1.71 for one layer geotextile,1.31～1.72 for one layer geotextile. The mechanism of geotextile soft rock granular soil fillings still obeys the principle of "quasi- cohesion". Its inner friction angelφnearly kept changeless, while its cohesion force c increases with the increase of geotextile layers. The constitutive relations of reinforced fillings may be described in Ducan-chang E-v model, and the parameters of Duncan-Chang model for geotextile-soil were identified from the tests.3. With the practical examples in engineering, the filling technology of geosynthetic badly weathered soft rock granular soil fillings embankments is thoroughly studied. Directed and engineering-valuable construction control technology and quality test method were obtained, which can be scientific references in the design and constructions of geosynthetic badly weathered soft rock granular soil fillings embankments.4. In accordance with topography and geologic framework features on site of Zhang-sang highway project, three dimensions geologic structure analysis model is set up. The computational procedure is developed by editing program with VC++6.0 Language, and Ducan-chang E-v model is embedded into the FLAC numerical simulating software which is used to analyze deformation and mechanical behavior of high filled embankment under dead weight in layer filling process.5. Based on the infiltration mechanism and engineering practice, the commonly used infiltration depth calculation formula for road embankments is analyzed, and practice application suggested that the Pradel & Raad formula is adaptable for calculating the infiltration depth in embankment. Taking in to account decrease in the strength for rain penetration, FLAC strength reduction method is used for analyzing the influence of rain penetration on additional settlement and stability of high filled embankments. |
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