A rotary-shear low to high-velocity friction apparatus in Beijing to study rock friction at plate to seismic slip rates

Abstract

This paper reviews 19 apparatuses having highvelocity capabilities, describes a rotary-shear low to highvelocity friction apparatus installed at Institute of Geology, China Earthquake Administration, and reports results from velocity-jump tests on Pingxi fault gouge to illustrate technical problems in conducting velocity-stepping tests at high velocities. The apparatus is capable of producing plate to seismic velocities (44 mm/a to 2.1 m/s for specimens of 40 mm in diameter), using a 22 kW servomotor with a gear/belt system having three velocity ranges. A speed range can be changed by 10 3 or 10 6 by using five electromagnetic clutches without stopping the motor. Two cam clutches allow fivefold velocity steps, and the motor speed can be increased from zero to 1,500 rpm in 0.1-0.2 s by changing the controlling voltage. A unique feature of the apparatus is a large specimen chamber where different specimen assemblies can be installed easily. In addition to a standard specimen assembly for friction experiments, two pressure vessels were made for pore pressures to 70 MPa; one at room temperature and the other at temperatures to

Flash Heating and Local Fluid Pressurization Lead to Rapid Weakening in Water‐Saturated Fault Gouges

“…To understand what happened within the gouge layers during the weakening, we plotted the data of frictional coefficient together with axial displacement in Figures 4a-4d. (Ma et al, 2014). 1) servomotor, 2) gear and belt system for changing velocity, 3) rotary encoder and potentiometer, 4) rotary shaft, 5) pressure vessel, 6) metal frame for fixing the pressure vessel, 7) axial loading column, 8) cantilever-type torque gauge, 9) axial displacement transducer, 10) thrust bearing, 11) axial force gauge, and 12) air actuator.…”

“…Experimental apparatus and sample assembly. (a) A schematic diagram of the low‐ to high‐velocity rotary shear apparatus at Institute of Geology, China Earthquake Administration (Ma et al, ). 1) servomotor, 2) gear and belt system for changing velocity, 3) rotary encoder and potentiometer, 4) rotary shaft, 5) pressure vessel, 6) metal frame for fixing the pressure vessel, 7) axial loading column, 8) cantilever‐type torque gauge, 9) axial displacement transducer, 10) thrust bearing, 11) axial force gauge, and 12) air actuator.…”

Shear‐Rate‐Dependent Behavior of Clayey Bimaterial Interfaces at Landslide Stress Levels

“…Studies on the shear behavior of bimaterial interfaces between soil and concrete, steel, geotextiles, and other manufactured materials, especially under low normal stresses ( σ n = 1–100 kPa), are abundant in the literature (e.g., Boukpeti & White, ; Eid et al, ; Ganesan et al, ; Ho et al, ; Lemos & Vaughan, ; Potyondy, ; Tsubakihara & Kishida, ; Wijewickreme et al, ; Zhang & Zhang, ). Equally, in fault mechanics, many researchers have been focusing on the slip‐ and rate‐dependent behavior of rock interfaces and thin gouge layers under high normal stresses ( σ n = 1–20 MPa) to understand the behavior of faults under subseismic and coseismic slip rates (e.g., Di Toro et al, , , ; Hirose & Shimamoto, ; Perfettini & Ampuero, ; Kitajima et al, ; Togo et al, ; Yao et al, , Ma et al, ; Yao et al, ). On the other hand, the rate‐dependent behavior of soil‐rock interfaces (e.g., Suzuki et al, , ) at typical landslides stress levels has received lesser attention.…”

Stick–slip behavior of Indian gabbro as studied using a NIED large-scale biaxial friction apparatus

“…However, they share a demerit of slow speed and limited displacement. Rotary-shear high-velocity friction experiments have been conducted in the last two decades and revealed dramatic weakening of faults as the slip rate approaches to a seismic slip rate on the order of 1 m/s (e.g., Di Toro et al 2011;Ma et al 2014; papers quoted therein). However, specimens used in rotaryshear friction apparatuses are thought to be too small to observe dynamic rupture propagation.…”