Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
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The Effect of Normal Load Oscillation Amplitude on the Frictional Behavior of a Rough Basalt Fracture
https://orcid.org/0000-0003-0118-8028
Abstract Quantifying the changes of frictional strength during dynamic normal loading is significant for investigations of joint and fault interaction as well as earthquake triggering. The frictional character of a natural basalt rock fracture with a rough surface is investigated by conducting well-controlled, repeatable direct shear experiments using a large-scale dynamic shear box equipment. Normal force oscillations, simulating a dynamic normal force, are applied to the fractured basalt sample. Simultaneously, a shear force acts on the lower block of the sample which provides a constant slip rate. The frictional behavior is investigated by applying a normal load with oscillation amplitude from 0 up to 80% of the initial normal load. Experimental results showed that the dynamic disturbance decreases the friction of the rock fracture, the minimum friction reduces with rising normal load oscillation amplitude. The dynamic disturbance enhances the maximum shear force under the smaller normal load oscillation amplitude. When the normal load oscillation amplitude exceeds a critical point, the maximum shear force reduces, even reaching “negative” values. Moreover, a phase difference (D1) is identified between peak normal load and peak shear load with peak normal load leading. There is also a phase difference (D2) between peak normal load and peak apparent dynamic friction coefficient. The phase difference of D1 rises with rising normal load oscillation amplitude, decreases with shearing, while, relative phase lag of D2 keeps constant. Our results confirm that dynamic normal force can both enhance and reduce the stability of a steadily slipping fracture depending on the normal force oscillation amplitude.
Highlights Dynamic normal load can both enhance and reduce the stability of the steadily creeping faults dependent on the normal load oscillation amplitude.A critical normal load oscillation amplitude is confirmed to judge the frictional strengthening or frictional weakening of the creeping rock fracture.A time difference between peak normal force and peak shear force with normal force ahead is confirmed.
The Effect of Normal Load Oscillation Amplitude on the Frictional Behavior of a Rough Basalt Fracture
https://orcid.org/0000-0003-0118-8028
Abstract Quantifying the changes of frictional strength during dynamic normal loading is significant for investigations of joint and fault interaction as well as earthquake triggering. The frictional character of a natural basalt rock fracture with a rough surface is investigated by conducting well-controlled, repeatable direct shear experiments using a large-scale dynamic shear box equipment. Normal force oscillations, simulating a dynamic normal force, are applied to the fractured basalt sample. Simultaneously, a shear force acts on the lower block of the sample which provides a constant slip rate. The frictional behavior is investigated by applying a normal load with oscillation amplitude from 0 up to 80% of the initial normal load. Experimental results showed that the dynamic disturbance decreases the friction of the rock fracture, the minimum friction reduces with rising normal load oscillation amplitude. The dynamic disturbance enhances the maximum shear force under the smaller normal load oscillation amplitude. When the normal load oscillation amplitude exceeds a critical point, the maximum shear force reduces, even reaching “negative” values. Moreover, a phase difference (D1) is identified between peak normal load and peak shear load with peak normal load leading. There is also a phase difference (D2) between peak normal load and peak apparent dynamic friction coefficient. The phase difference of D1 rises with rising normal load oscillation amplitude, decreases with shearing, while, relative phase lag of D2 keeps constant. Our results confirm that dynamic normal force can both enhance and reduce the stability of a steadily slipping fracture depending on the normal force oscillation amplitude.
Highlights Dynamic normal load can both enhance and reduce the stability of the steadily creeping faults dependent on the normal load oscillation amplitude.A critical normal load oscillation amplitude is confirmed to judge the frictional strengthening or frictional weakening of the creeping rock fracture.A time difference between peak normal force and peak shear force with normal force ahead is confirmed.
The Effect of Normal Load Oscillation Amplitude on the Frictional Behavior of a Rough Basalt Fracture
https://orcid.org/0000-0003-0118-8028
Abstract Quantifying the changes of frictional strength during dynamic normal loading is significant for investigations of joint and fault interaction as well as earthquake triggering. The frictional character of a natural basalt rock fracture with a rough surface is investigated by conducting well-controlled, repeatable direct shear experiments using a large-scale dynamic shear box equipment. Normal force oscillations, simulating a dynamic normal force, are applied to the fractured basalt sample. Simultaneously, a shear force acts on the lower block of the sample which provides a constant slip rate. The frictional behavior is investigated by applying a normal load with oscillation amplitude from 0 up to 80% of the initial normal load. Experimental results showed that the dynamic disturbance decreases the friction of the rock fracture, the minimum friction reduces with rising normal load oscillation amplitude. The dynamic disturbance enhances the maximum shear force under the smaller normal load oscillation amplitude. When the normal load oscillation amplitude exceeds a critical point, the maximum shear force reduces, even reaching “negative” values. Moreover, a phase difference (D1) is identified between peak normal load and peak shear load with peak normal load leading. There is also a phase difference (D2) between peak normal load and peak apparent dynamic friction coefficient. The phase difference of D1 rises with rising normal load oscillation amplitude, decreases with shearing, while, relative phase lag of D2 keeps constant. Our results confirm that dynamic normal force can both enhance and reduce the stability of a steadily slipping fracture depending on the normal force oscillation amplitude.
Highlights Dynamic normal load can both enhance and reduce the stability of the steadily creeping faults dependent on the normal load oscillation amplitude.A critical normal load oscillation amplitude is confirmed to judge the frictional strengthening or frictional weakening of the creeping rock fracture.A time difference between peak normal force and peak shear force with normal force ahead is confirmed.
The Effect of Normal Load Oscillation Amplitude on the Frictional Behavior of a Rough Basalt Fracture
Dang, Wengang (Autor:in) / Konietzky, Heinz (Autor:in)
2022
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
38.58$jGeomechanik
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB41
| British Library Online Contents | 2018
Experimental investigation on frictional properties of stressed basalt fractures
| DOAJ | 2023