Study On The Activity Of Chenghai Fault Zone And Its Influence On The Stability Of The Jinsha River Bridge Over Taoyuan

The correlation research between activity structure and engineering construction is one of the most fascinating frontier disciplines in contemporary geosciences.The proposed Taoyuan Jinsha River Bridge is located above the Chenghaida Fault Zone,and the fault zone has a direct impact on the stability of the site and the safe operation of the site.Therefore,the current activity study of Chenghai fault has important practical significance for the construction of the bridge project and its safety evaluation.This paper takes the Chenghai fault zone as the research object,and conducts related analysis and research on its tectonic characteristics through field typography,and combines the collection,sorting,and induction of research data such as geophysical fields,earthquakes,and tectonic stress fields,and the fracture activity.Conduct analysis and discussion.The investigation of the Chenghai fault from Yongsheng to Binchuan was carried out in detail.According to the fracture characteristics and activity differences,it was divided into three sections in the north,middle and south,and the relevant characteristics of the fragmentation activities were summarized.In addition,the paper also combined the finite element analysis software ANSYS stress field simulation technology to carry out the relevant numerical simulation of the structural stress field of the Chenghai fault zone and intuitively reflect the stress distribution of the fracture.Relying on the related construction projects of the Jinsha River Bridge of Taoyuan,the geological conditions of the site surveyed on the site,the application of polar projection and the bank slope stability analysis software were studied.Finally,through the study of regional structural stability analysis,engineering effect analysis and bridge site area suitability evaluation,the comprehensive evaluation and summary of the relationship between the activity of the Chenghai fault and the construction of the bridge are carried out.The research results show that the north part of the fault is an arc-shaped knob structure system that protrudes to the east and protrudes.The main activity feature is the extension normal fault.The activity rate is between 0.04 and 0.26mm/a;the middle section is Chenghai-Jinna.The fractures are divided into the Chenghai Basin,Qingshui Basin and the Jungna Basin according to the controlled basins.The Chenghai Basin fault is dominated by normal faults,and the Qingshui Basin faults have strike-slip-pull activity.Characteristics: The faults of the Jingna Basin have a normal fault and a left-lateral strike-slip nature.The faults in the southern segment are typical of a braided tectonic system and are dominated by normal fault activity.Some faults have left-lateral strike-slip characteristics.Between 0.1 and 0.95mm/a.Through numerical simulation of the structural stress field,the results show that the maximum principal stress of the fault is high in the north,low in the south,weak in the west and strong in the east.The stress is mostly concentrated in the basalt area.The minimum principal stress is a piecewise character,and the strain energy is mainly concentrated in the north of the simulation area.Part of the basalt area.The results of the simulation of the bridge site area show that the bridge site area is a stress concentration area within a certain range on both sides of the fault.The bridge is located within the Chenghai fault and is a sudden drop in stress area.In addition,due to the fracture above the bridge site,the stability of the regional structure,the evaluation of the suitability of the bridge area and the results of the stability analysis of the slope indicate that the stability of the regional structure is poor,the suitability of the bridge area is poor,and the slope of the bridge is relatively high.Stability is basically suitable for construction.