| Doujiangyan-Wenchuan Road including two secondary roads and highways, and two secondary road was called "life road" in the earthquake of 2008 in Wenchuan, it is the main channel to earthquake disaster region. Along the mountain road is prone to geological disasters, and geological tectonic environment along the highway become more complicated and serious after WenChuan earthquake. Huge amount of the secondary geological disasters have been induced along the road, secondary geological disaster along the road mainly includes collapse landslide and debris flow and has serious endanger road safety. So it is very important for ensure the roads safe passage for a long time to analysis and research types and causes of secondary geological disasters and forecast evaluation Secondary geological disaster risk and conduct research secondary geological disaster prevention measures along the road.This paper expounds the regional geological tectonic environment along the road, summarizes the development features and distribution rules of secondary geological disasters including collapse landslide debris flow:Classifying collapse landslide debris flow of secondary geological disasters from various angles and summarizing the causes of each type of disasters based on the principle of road safe passage; According to the characteristics of secondary geological disasters will be long-term latent Using layer analysis method and fuzzy mathematical method with Dou-Wen road as an example to establish secondary geological disasters in the mountainous area highway monomer predictive secondary geological disaster risk evaluation system and mountainous area highway comprehensive prediction evaluation system;Analysis the secondary geological disasters of Dou-Wen road existing protective measures and effect and studying the secondary geological disaster along mountain road prevention measures. The main understandings and conclusions are as follows:(1) By collecting a large number of secondary geological disaster data and field investigation, we know that secondary geological disasters along the Dou-Wen road mainly includes collapse landslide mud-rock flow. Collapses and landslides are the most influence on the road when during the earthquake, but collapses and mud-rock flows become very serious after the earthquake.(2) Development and distribution characteristic of secondary geological disasters along the Dou-Wen road comprehensive influenced by geographic and geomorphic, strata’s lithology, geological structure, hydrology, and earthquake, rainfall. By analyzing the typical secondary geological disasters along the road, research the influence factors, genetic mechanism and damage level, harm way of disaster body based on the classification research of different secondary geological disasters.Now the collapse of impacting on roads mainly distributed in the inside of slopes, with dangerous rock mass slope and slope toe are primarily; The collapse of tunnel entrance Is also a kind of secondary disasters that serious impacted on road safety. Landslides mainly in soft rock strata cutting excavation slope shallow rock mass and strong weathering layers of sliding failure, and they are more small landslides. There are many debris flows along the minjiang river valleys and the development of slope mass on both sides, main causes of debris flow disasters is due to a large number of debris flow provenance and start rainfall threshold significantly reduced, the risk of many large-scale and high frequency debris flow is very easy.(3) Based on the distribution characteristics, influencing factors and damage ways to roads of secondary geological disasters along the mountain road, Using analytic hierarchy process and fuzzy mathematics method, set up mountain area highway landslides during the collapse secondary geological hazards risk prediction secondary geological disaster risk evaluation system and mountainous area highway comprehensive prediction evaluation system.(4) Collapse secondary geological disaster along the Dou-Wen road risk prediction and evaluation results:high risk for 62.5% of total collapse, No risk of 22%, Low risk and medium risk accounts for about 15.5%; landslide secondary geological disaster along the Dou-Wen road risk prediction and evaluation results: cutting of shallow landslide is a high risk, the instability of natural slope soil body overall landslide disaster risk is smaller; mud-rock flow secondary geological disaster along the Dou-Wen road risk prediction and evaluation results:high risk for a total of 26%, High risk of 33%, medium risk sections of total section 30%, Very low and low risk sections of total section 11%.(5) Establish secondary geological disaster along the mountain road risk of comprehensive prediction and evaluation system, that comprehensive prediction and evaluation system combined with points of evaluation and linea r evaluation. Predict the evaluation results show no dangerous section chief to account for all of the 45.52, low risk sections of total section 1.86, medium risk sections of total section 11.53, high risk of total road sections 41.09.(6) Secondary geological disaster along the Mountainous road, protection principle is the first principle to ensure a smooth flow of traffic road. It is important to pay special attention to the characterized of linear vulnerability and control space is narrow in the mountainous area road along the river. The protection of Secondary geological disaster should pay attention to grasp the protection time and Combine with the emergency protection and governance in the long run, at the same time, we should constantly improve the ability to resist disasters of rad system itself.(7) Collapse of the secondary geological disaster prevention and control measures is given priority to with flexible protection, a large number of use hanging net supporting measures with Slope toe block stone wall, retaining wall, facing wall, slope toe wall, etc. Total protection section of about 46.15% in line with the passive protective net, about 31.67% of the active network protection, about 44% of stone cut off wall and retaining wall, about 20.67% of facing wall and accusative revetment structure. Protection measures main includes these four protective measures and their combination patterns.(8) By analyzing the common protection measures, Existing protective measures and protecting effect of landslide, collapse, debris flow, summing up the problems existing in the secondary geological disaster protection and put forward the corresponding treatment suggestions. Take flexible protective measures with simple construction, low cost, change to use to prevention and control small scale collapse of the secondary geological disasters along the road; Carrying out special research and. putting forward new type protective measures for large deposit dangerous rock body and collapse. Avoiding for large oversize landslide and high-speed remote landslide that were directly induced by the earthquake, Small cutting landslide should adapt general landslide protection measures, landslides in the valleys in the basin regard them as lndslide and mud-rock flow, taking special prevention and control technology research and putting new control technologies for some landslides that can not avoid but the toad must pass the large-scale landslide. By analyzing the common protection measures, Existing protective measures and protecting effect of debris flow, Combining with the characteristics of debris flow distribution and damage ways to roads, putting up the problems existing in the secondary geological disaster protection and put forward the corresponding treatment suggestions.(9) Research and analysis the secondary geological disaster chain mechanism, and putting forward the typical secondary geological disaster chain model and protective measures. Secondary geological disaster chain protection should pay attention to single disaster protection and disaster chain;protection key is defending and disaster link point. |
PDF Full Text Request