The Interaction Mechanism And Assessment Of Highway Engineering Construction And Environment In Southwest Mountain Area Of China

Environment impact assessment is an issue of important study of highway construction project for the sustainable development. The road engineering construction cannot leave certain natural environment, also especially is close to the geological environment relations. The road engineering construction and the geological environment detuning may cause geological environment's aggravation, as well as the secondary geological disaster. Therefore, as to the complex west mountainous area that in exploitation of western China and the transportation demands rapid growth, strengthens to the mountain road engineering geological environmental effect mechanism research in order to control or the reduction of the secondary geological disaster and creates from it to the geological environment perturbation is imminent. As a consequence, this article combines with the Supported by National Science Foundation of China "the western region of major road projects and environmental interaction mechanism", take the XiPan highway as example, analysis the context of the conditions of the built environment in the mountain road engineering. We start from the geological environment quality and impact factors of road construction projects on the geological environmental along the road, study the impact and constraints of geological environment to mountain road engineering and the mountain road engineering' mechanism of environment affection, road engineering and geo-environment interaction and soil erosion law during the road construction projects. It has obtained the following research results:(1) The regional geology background condition and the engineering geology condition along the route of the highway from Xichang to Panzhihua has been Analyzed in detail; Due to the complexity of the geological environment of mountain road engineering, lower grades of the line, and bad construction conditions, together with the misconduct in construction and other reasons, the withstand disaster capacity of the project becomes low, and make mountain road obviously vulnerable. The impact of geological environment on the mountain road engineering construction mainly reflected in the following respects: constraints on the alignment of road and methods of construction along with construction conditions, the high request of individual project's requirements as well as the road maintenance requirements. Different geological environment conditions to different extent and in different ways affect the road engineering.(2) The environmental impact mechanism of the road construction has been analyzed. The impact of the road construction on geological environment reflects in various stages of road construction. Road design stage, as a result of the negligence of engineering investigations, unreasonable route selection and design may cause varieties of short-term or potential destruction of the geological environment; during road construction process, due to the excavation of rock and soil and road making, improper treatment of the waste soil, which will have a serious impact on the geological environment.(3) Based on analysis of geological environment quality influence factor along the Xichang-Panzhihua freeway line assessment index system and hierarchal analysis model for geological environment quality was established. In establishment of the system and model above, eight factors such as geological construction, rock composite and so on was selected; The assessment of geology environment quality along the 2km scope of Xichang-Pangzhuhua highway was carried out with fuzzy synthetic evaluation method and GIS database.(4) Based on analysis of geological environment and engineering construction activities along the Xichang-Panzhihua freeway line assessment index system and hierarchal analysis model for impact of highway engineering on geological environment was established in four aspects of ground stability, rock and soil mass stability, engineering activities and geological disaster. In establishment of the system and model above,12 factors such as geological construction, rock composite and so on was selected. The assessment of influence degree of highway construction on geological environment was carried out with fuzzy synthetic evaluation method and GIS.(5) In order to investigate the behavior of soil erosion on the slope of the different underlaying surface during construction, the experiment with natural rainfall on Xi chang-Pan zhihua highway was conducted, to quantify the runoff and soil loss. The results show that:â‘ During the expressway construction, the main type of soil erosion is gully erosion. The majority down wash of sloping surfaces accumulate at the base of slope (or pedestal sit of slope) and the pavement. But the mass which flow into the river system generally does not exceed 10% of the whole amount of soil erosion.â‘¡The half-width precipitation are the principal factors that cause soil erosion on the slope of the embankment. The amount of erosion and sand output has good linearity relativity with the half-width precipitation. The catchment area precipitations are the principal factors that cause soil erosion on the cutting slope. The amount of erosion and sand output has good linearity relativity with the catchment area precipitation. The platform precipitations are the principal factors that cause soil erosion on the catchment platform of the dumped soil area slope. The amount of erosion and sand output has good linearity relativity with the platform precipitation.â‘¢The experimental model to predict soil erosion on the slope has guiding significance to water and soil conservation during highway construction. According to the preliminary experimental study result, the catchment surface is the principal factors that cause soil erosion on the slopes. The drainage of catchment surface is important measure of reduce soil erosion in mountainous area highway construction.(6) Based on interaction mechanism analysis of road engineering construction and geological environment, we inquire the interaction law of road projects and the geological environment. Road construction and geological environment are inter-relationship and influence each other; road geological disasters' adverse effects on geological environment is the deterioration of the geological environment, so is the decline of environment quality; geological environment' adverse effects on road geological disasters is the deterioration leads the road geological disasters increased, along with the frequency and intensity increased.