| Tunnel drilling jumbo is a necessary equipment for drilling and charging in the mechanized construction of tunnel drilling and blasting method.With the comprehensive improvement of construction technology concept,method and mechanization level in China,its application scope and importance have been greatly improved in the tunnel construction of drilling and blasting method in China.At the same time,the construction focus of China’s railway and highway tunnel projects has shifted to the southwest region with complex and changeable geological conditions,especially the ’ first step ’ Qinghai-Tibet Plateau.The large-scale bad geology and major engineering disasters that may be encountered in the construction of the project make the advanced geological prediction work more and more important.However,the traditional artificial advanced geological prediction method has been difficult to match the high efficiency and few people working conditions of the mechanized construction tunnel of the plateau drilling and blasting method from the timeliness and labor intensity.Therefore,it is of theoretical and engineering value to carry out the research on the mechanized advanced detection technology with the simultaneous construction.At present.researchers at home and abroad have carried out some research on the advanced geological prediction of seismic waves in the mechanized construction of drilling and blasting method,but there are few reports on the advanced prediction of the drilling source of the drilling jumbo in the construction.The main reasons are that the source excitation mechanism of the drilling jumbo is unknown,the continuous random seismic signal is difficult to use,and the lack of advanced prediction equipment for highly mechanized construction of related matching.In this paper,a series of studies on the prediction of drilling source of tunnel drilling jumbo are carried out by means of theoretical analysis,field test,laboratory test and numerical simulation.A series of research results with certain theoretical value and practical engineering application effect are obtained.The main contents are as follows:(1)Aiming at the problem that the excitation mechanism of the drilling source of the drilling jumbo is unknown,based on the field measured signal,the rock breaking behavior characteristics of the drilling jumbo of the commonly used model in the field are summarized and analyzed.Through the spectrum analysis and time-frequency analysis of the measured pilot signal of the drilling source,the characteristics of the drilling source received at different positions of the tunnel drilling jumbo are obtained,and the optimal installation position of the pilot detector is given.Based on the theory of elastic mechanics,the formula of seismic wave displacement caused by concentrated point source and double couple point source is derived,and the mathematical representation of displacement field radiation pattern of impact and cutting behavior is given.The mechanism of vibration displacement field under impact-cutting coupling of rock drilling jumbo is revealed,which provides a theoretical basis for subsequent data processing research.(2)Aiming at the problem that the influence of drilling parameters of drilling jumbo on the characteristics of excitation source is not clear,a multi-functional indoor test platform for tunnel drilling jumbo is innovatively developed,which realizes the wide-area,independent and hierarchical control of the main drilling parameters of the jumbo,such as impact pressure,impact frequency and rotation speed,and the real-time monitoring of the reference signal of drilling source,drilling speed,drilling pressure,torque and confining pressure of the specimen.The variation law of the main frequency position and energy level of the seismic source reference signal of the trolley under different drilling parameters and similar physical attribute rock conditions is systematically analyzed.The regression analysis and prediction method of drilling parameters-seismic source characteristics is proposed,which provides a basis for the selection of band-pass filter parameters of this research detection method.(3)Aiming at the problem of seismic record recovery from continuous multiple wave interference of punching-shear coupling borehole vibration,a single equivalent pulse extraction method based on least square deconvolution and cross-correlation is proposed to filter out the periodic noise of rotation and improve the signal-to-noise ratio.Based on the characteristics of continuous drilling of rock drilling jumbo,the noise distribution characteristics of signal sections at different depths of reference signal are analyzed,and the principle of optimal selection of reference signal time window is established to suppress random noise,surface wave and other interference,so as to further improve the signal quality.The whitening filter is designed and improved.Combined with Hilbert-spectral whitening algorithm and adaptive modal decomposition algorithm,the effective instantaneous modal piecewise gain effect is achieved,which solves the blindness problem of traditional spectral whitening gain,and the signal-to-noise ratio is improved by 60.96%.Finally,a deconvolution-VMD-spectral whitening combined drilling seismic record recovery method was formed,and a clear seismic record recovery was achieved.(4)In view of the lack of advanced detection equipment suitable for the drilling source of the tunnel drilling jumbo,combined with the highly mechanized supporting conditions of the drilling and blasting tunnel,a wireless detection equipment for the drilling source of the drilling jumbo including data acquisition,remote control and remote transmission functions is developed,which realizes the large-capacity high-speed buffering,on-chip storage and highprecision synchronization of the data in the complex environment of the tunnel.Based on the equivalent pulse seismic record recovery,the conventional seismic record processing method is introduced,and the migration imaging technology suitable for the detection of tunnel drilling jumbo is summarized.The field double-blind experiment is carried out to verify the effectiveness of the method in the field practical engineering application,which provides technical and equipment support for the development of " drilling while exploring " in the mechanized construction of tunnel by drilling and blasting method. |
PDF Full Text Request