Hysteretic effect considered monitoring model for interpreting abnormal deformation behavior of arch dams: A case study

Abstract

Summary Deformation is the most intuitive reflection of comprehensive behavior of concrete dams; it is of great significance to predict and interpret the deformation observation data for dam health monitoring. The world's highest concrete dam, Jinping I arch dam in China, was discussed in this paper. Aiming at its annually measured continuous growth phenomenon of dam body deformation towards the downstream direction when reservoir keeps stable at the normal water level of 1,880.0 m, influences of cement hydration heat‐induced temperature rise effect, valley contraction, and dam material creep on deformation behavior of this dam were estimated by finite element method (FEM) and the measured data. Combined with the results of the hydraulic, seasonal, and time (HST) model, the abnormal deformation behavior was detected to be jointly caused by the hysteretic hydraulic deformation and the ambient temperature drop effect. Subsequently, to solve the deficiency that the traditional HST model cannot reasonably explain this measured deformation behavior, a hysteretic hydraulic component was introduced into the HST model, and a special hydraulic, hysteretic, seasonal, and time (HHST) model was proposed. Based on the numerical simulation of viscoelastic FEM and the constrained least square method, the newly added component was represented by a continuous piecewise fitting function, with model factors of previous relative water depth and cumulative days of the current water level stage. HHST model results of Jinping I arch dam show that the measured abnormal displacement increment of dam body is 70% caused by the ambient temperature drop effect and 30% caused by the viscoelastic hysteretic hydraulic deformation.

Displacement monitoring model of concrete dams using the shape feature clustering‐based temperature principal component factor

“…The coefficients of these two components are shown in Tables 1 and 2, respectively. The hysteretic effect has been already discussed in Wang et al 19…”

“…Namely, the measured time series expose a continuous growth phenomenon of the radial displacements toward the downstream direction for reservoir water level constant at the elevation of 1,880 m ( Figure 6, black line), due to the viscoelastic hysteretic hydraulic deformation. The hysteretic hydraulic component is related to the water load level and load holding time and is defined by relative values as follows 19 :…”

“…Hu et al 18 presented an hydraulic, thermal, crack, and time model to diagnose the deformation behavior of the Chencun concrete arch dam with horizontal cracks. For the Jinping-I arch dam, Wang et al 19 proposed an hydraulic, hysteretic, seasonal, and time (HHST) model to quantify the contribution of causal factors of continuously increasing radial displacements at the constant water-level elevation of 1,800 m.…”

Two spatial association–considered mathematical models for diagnosing the long-term balanced relationship and short-term fluctuation of the deformation behaviour of high concrete arch dams

“…To interpret this abnormal deformation behaviour, the authors have studied the potential causal factors of the concrete hydration heat-induced temperature rise effect, bank slope extrusion, air temperature drop effect and dam concrete creep, and the last two were found to be reasonable for this phenomenon. 25 With the generalized Kelvin model representing a viscoelastic constitutive model for dam concrete, under the hydrostatic pressure corresponding to the measured upstream reservoir water level, the hysteretic hydraulic displacement caused by concrete creep was calculated by finite element method (FEM) and shown in Figure 8.…”

Hybrid hydraulic‐seasonal‐time model for predicting the deformation behaviour of high concrete dams during the operational period

“…These influences are interrelated, which are difficult to be described theoretically. Numerical simulations can objectively simulate the comprehensive effects of multiple factors on structural behaviours of concrete dams 25–30 . Such methods provide an effective way to solve the problem mentioned above.…”