Effect of using grouted vertical barrier on seepage characteristics under small hydraulic structures

Abstract

This study investigated the effect of using Grouted Vertical Barrier (GVB) on the seepage characteristics (uplift force, seepage rate, and exit hydraulic gradient) under small hydraulic structures. The GVB’s variables, viz., position, depth, width and hydraulic conductivity, were studied experimentally using sand model and numerically employing SEEP/W software. A parametric study investigated several cases of the variables after numerical model verification. The results depicted that the heal and toe ends were the best positions for uplift force and exit gradient, respectively. The maximum reduction in the seepage occurred at both ends. The seepage characteristics swiftly decreased by increasing the GVB’s depth in the pre-mentioned best positions. Upsurge of the GVB’s width sequentially reduced the exit gradient and the seepage rate, whilst negatively impacted the uplift force. Declining the ratio between the hydraulic conductivity of the GVB (K) and the reference soil one (Ko) significantly lowered the seepage until reaching a stationary proportion K/Ko = 1E−4. Beyond this, decreasing K/Ko ratio do-nothing. Through regression analysis, three equations were developed to estimate the seepage characteristics affected by GVB’s variables. The indications of comparative studies revealed a better effect of the GVB compared to any of the sheet pile or the upstream blanket. Keywords: Seepage characteristics, Grouted vertical barrier, Small hydraulic structures, Sheet pile, Upstream blanket