Research On Seismic Ground Motion Indices For Operation Control And Single Station Earthquake Early Warning Applied For High-speed Railway

Earthquake early warning is one of the effective means of protecting againstand mitigating earthquake disasters developed in recent years. China is anearthquake-prone country. Earthquake is a natural disaster which probabilityis small but hazards to railway safety is high. With the rapid development ofhigh-speed railway, it is urgent for Chinese high-speed railway construction ofearthquake early warning system.Aiming at solving the key technical problems of earthquake disasterprevention system in Chinese high-speed railway, the development history ofthe Japanese Shinkansen earthquake monitoring and earthquake early warningsystem was reviewed, the current status of earthquake ground motionparameters for operation control and the key technology of the earthquakeearly warning were summarized. Related research focused on earthquakeground motion indices and the rapid estimated method for focal parameters insingle-station earthquake early warning was developed, based on the keytechnology of the earthquake early warning for Japanese Shinkansen andground motion data. Overview of the research results is as follows:(1) Based on Japanese Shinkansen alert seismometer band-pass filter, theband-pass filter applied in Chinese high-speed railway was developed, and thedesign method and recursion equation of IIR digital band-pass filter werepresented.(2) Using Japanese K-net strong motion data and Chinese CSMNC strongmotion data, the statistical relationships between several ground motionparameters were set up. These ground motion parameters included, JapaneseMeteorological Agency seismic instrumental intensity-I jma, Chinese seismicinstrument intensity standard-I s, Peak Ground Acceleration, SpectralIntensity-SI, Arias Intensity-I a, Cumulative Absolute Velocity-CAV,Cumulative Differential of Energy-DE, the linear dependence between groundmotion parameters was analysed. The relationships between ground motionparameters and the earthquake damage distribution were presented, using thedata of Japanese Shinkansen viaduct column damage distribution in threegreat earthquakes and the data of K-net stations and KiK-net stations alongthe Tohoku Shinkansen.(3) According to the statistical relationships between ground motionparameters, the threshold value for other ground motion parameters wasanalysed by converting, corresponding to the threshold value for Peak GroundAcceleration(alarm value:40gal, speed-limit value:80gal, stop value:120gal). Using false alarm and fail alarm analysis and the realtime analysis forthe alarm value and the rationality analysis for the speed-limit value and stopvalue, combining with the statistical relationships between ground motion parameters and the relationships between ground motion parameters and theShinkansen viaduct column damage distribution, the ground motion indicesand corresponding threshold value were presented. The feasibility of theground motion parameters calculating from vertical component as the alarmvalue was studied.(4) Based on single-station estimating epicentral distance method, B-Δ method,which uses initial amplitude growth rate after P-wave arrival, through thetheory form B-Δ method, using Chinese CSMNC strong earthquakeobservation data to verify C-Δ method by linear fitting initial amplitudeenvelope of P-wave, this method can get ideal epicentral distance estimationresults after0.5seconds P-wave triggered. Facing to defects of this method ina realtime application, A-Δ method of using Arias Intensity initial amplitudegrowth rate after P-wave arrival to estimate the epicentral distance is proposed.The results show that this method can get stable the epicentral distanceestimation results after0.7seconds P-wave triggered.(5) The magnitude scaling relationships using τpmax, τcand Pd from the first3sof P-wave arrivals based on Chinese CSMNC strong motion data wasdeveloped. The results of error analysis have shown that the magnitudeestimation of Pd is optimal. The linear proportional relationship betweenP-wave square velocity IV2pand the full-wave square velocity IV2wasdeveloped. A continuous magnitude estimation method using square velocityIV2was presented. The results show that this method can get optimal resultafter5seconds P-wave triggered.