Investigation into Energy Dissipation During Grouting Uplift
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ORIGINAL PAPER
Investigation into Energy Dissipation During Grouting Uplift Juan Chen1
•
Xian Yang1 • Feng-ling Li2
Received: 10 October 2019 / Accepted: 27 April 2020 Ó Indian Geotechnical Society 2020
Abstract Concrete covering damage is often caused by inadequate control of the grouting process. As such, in this work, a grouting nonlinear dynamic damage model was established to explore the concrete covering damage mechanism, which is crucial to the safety of dam grouting. Specifically, this study was designed to: (1) investigate the hysteresis energy dissipation and hysteresis damage mechanisms during the concrete covering’s dynamic response process and (2) assess the concrete covering’s nonlinear dynamic response and hysteresis energy dissipation under different grouting pressures, joint apertures, cement liquid viscosities, and grouting flows. The results show that the pulsation amplitude and cumulative hysteresis energy dissipation signifcantly affects the concrete covering damage rate, which quickly increases with damage energy dissipation rate in unstable grouting pressure. Keywords Concrete covering Hysteresis energy dissipation Grouting Hysteresis loop Damage deformation
Introduction In shallow joint rock masses, consolidation grouting relies on repeated production of high pressure to improve the impermeability between the rock foundation and concrete & Juan Chen [email protected] 1
Hunan University of Science and Technology, Xiangtan 411201, China
2
Changsha University of Science and Technology, Changsha 410076, China
covering. The upper limit grouting pressure value is set by the uplift displacement value during grouting, which in turn is affected by the rock mass’s grouting parameters, joint aperture, and damping characteristics. When the concrete covering is actively uplifting, reducing the grouting pressure does not immediately reduce or even stabilize the concrete covering’s displacement [1]. As a result, controlling the concrete covering uplift displacement is extremely challenging, and failing to do so can lead to concrete covering damage and deformation. Many scholars have found that rock masses under dynamic loading often exhibit nonlinear elastic behavior and show hysteresis characteristics. Erarslan et al. investigated sedimentary rocks displaying nonlinear elastic behavior and determined that nonlinearity is strongly a function of frequency, strain amplitude, and the saturating fluid properties [2–4]. Deng et al. found that the stress–strain hysteresis time is not constant, but instead, is obviously larger at the initial cycle loading and unloading stage and the stage when destruction is approaching [5]. According to Xi et al., the rock and rock mass properties are very different from other materials that have strong nonlinear elastic behavior and hysteresis characteristics [6, 7]. McCall et al. used a microscopic model unit to study the dynamic mechanical properties and the mechanical behavior of rocks under static loading and determined that the wave propagation proces
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