Research on Seepage of Jointed Rock Mass of Tunnel and Limited Discharge of Grouting

Abstract

In underground engineering such as tunnel engineering, the condition of surrounding rock such as water-containing jointed rock mass is a common engineering geology. For broken, water-containing surrounding rock, the reasonable measures to prevent and drain water has always been a key issue. Based on the statistical information of the structural surface of the surrounding rock of the Hongtuzhang tunnel, DIPS software was used to classify the structural plane of the tunnel. Based on the statistical analysis of the occurrence, size, and density of the structural plane, the two-dimensional structural plane network model of the rock mass was established, and the permeability tensor (K1 = 1.61 × 10−6 m/s, K2 = 5.78 × 10−7 m/s) was calculated. Consider the worst orientation, the permeability tensor (K1 = 1.61 × 10−6 m/s) was selected to calculate the grouting design. Based on the theory of limited discharge, the influence of parameters of permeability coefficient ratio n and thickness of grouting layer Tg on the tunnel water inflow and lining external water pressure was analyzed. The recommended value of tunnel drainage was 3.0 m3/m∙d, then the corresponding grouting circle parameters were put forward (permeability coefficient ratio n = 100, thickness of grouting layer Tg = 8 m).

Keywords

• jointed rock mass
• seepage
• permeability tensor
• permeability tensor of grouting layer
• grouting layer thickness