Research On The Mechanism Of Landslide Disaster Evolution In Red Layer Area Based On Multi-source Data Fusion

The total distribution area of the Cenozoic red layer in China is about 59.53×10~4km~2,among which the distribution area of the red layer in southwest China is 23.27×10~4km~2,accounting for 39.09%of the national red layer area.With the rapid development of China’s economic construction,linear projects such as highways and railways have been continuously planned,constructed and operated in areas with complex geological conditions.The red beds have become a rock and soil mass that cannot be avoided in the construction of linear projects.The red beds are relatively poor in its engineering geological properties,and many types of geological hazards are encountered during the construction of highways and railroads and in the operation and maintenance phase,which often produce large economic losses and bring serious threats to the safety of highways,railroads and other linear engineering construction and operation and maintenance,directly endangering people’s lives and property safety.For this reason,this paper relies on the National Key Research and Development Program:Mechanisms of geological body destabilization and catastrophic mode of linear engineering traversal cutting in the red beds region(2018YFC1504901)、Multi-dimensional multi-field detection and monitoring equipment and early warning technology for typical geological hazards in red layer areas(2018YFC1504903)and"Innovation Star"project of Gansu Province:Research on Landslide Disaster Mechanisms and Early Warning Indicators in Red Layer Areas Based on Data Fusion(2021CXZX-632).The Chengdu Tianfu International Airport Expressway TJ04 section K17+700 to K17+900 in the southwest red beds area and the Chongqing Xiaojiabao cut-layer landslide in the Hangzhou-Lanzhou line from Fengjie to Yunyang in the southwest red beds area(B13 standard)RK97+780 to RK98+010 were selected as typical geological hazard cases.Through engineering geological analysis and indoor model tests,based on multi-source data fusion method.The disaster evolution process of two types of typical landslides in the red-stratified area is studied in depth,and the following conclusions are drawn:(1)Based on the basic structure system of the multi-source data fusion system,aiming at the characteristics of multi-source,heterogeneous and massive geological disaster monitoring data in the red-bed area,a method for analyzing the evolution mechanism of landslide disaster in the red-bed area based on multi-source data fusion is constructed;(2)The geological analysis concluded that the main reason for the formation of the new airport road cut-level landslide in Chengdu is the infiltration of surface water and the excavation of the roadbed at the front edge of the landslide.The main reasons for the formation of the Xiaojiabao cut-level landslide in Chongqing are the slope structure,surface water infiltration and the excavation of the roadbed at the front edge of the landslide;(3)The multi-source data pre-processing revealed that the smoothing by the adjacent mean method and the Savitzky-Golay filter fitting method were effective in extracting the average trends of the time series curves of pore water pressure and matrix suction during landslide hazard monitoring;(4)The fusion of sensor data and statistical probability analysis show that the change curve of water content and cumulative rainfall are significantly correlated and the change curve of pore water pressure and water content are highly correlated with the increase of rainfall ephemeris in cascading landslides,and the pattern of cut-layer landslides is similar,indicating that rainwater infiltration is the direct cause of the increase of water content and pore water pressure in red-layer landslides in the southwest;(5)Through comprehensive geological characteristics analysis and model test data characteristics,combined with data fusion analysis,the evolution mechanism of Chengdu Taiping Town cascading landslide is as follows:excavation of slope→slope body cracks→rainfall infiltration→slope local slump→surface water infiltration intensifies→soil water content rises→pore water pressure increases→slope instability→overall traction slide;(6)Through comprehensive geological characteristics analysis and model test data characteristics,combined with data fusion analysis,the evolution mechanism of Chongqing Xiaojiabao cut-layer landslide is as follows:excavation disturbance→rock unloading and pulling crack→rainfall infiltration to the residual slope layer→residual slope layer sliding down the wrong→rainfall infiltration to the strong weathering layer→slope foot dumping and falling over→rainfall infiltration to the weak interlayer→weak interlayer absorbing water and softening,sliding along the weak surface→slope top dumping and staggering→slope dumping-sliding compound damage.