地表预注浆加固公路隧道浅埋偏压破碎围岩效果分析

TREATMENT EFFECT ANALYSIS OF SHALLOW-BURIED CRUSHED SURROUNDING ROCKS UNDER UNSYMMETRICAL PRESSURE REINFORCED WITH SURFACE PREGROUTING TECHNOLOGY IN HIGHWAY TUNNEL

针对广福隧道一段浅埋偏压破碎围岩的实际情况,为提高围岩强度,降低围岩的通透水性能,改善隧道成拱的作用,进而达到保护水资源、保证工程安全之目的,提出了采用水泥单液浆和水泥水玻璃双液浆的地面高压预注浆处治措施,并通过数值计算和现场试验详细分析了处治效果。综合分析表明:注浆处理后,围岩完整程度和强度明显提高,隧道断面净空收敛和拱顶下沉稳定速度较快,最终变形值较小,初期支护和二次衬砌整体受力特征得到很大改善,注浆处治效果非常显著。

Considering the case of shallow-buried crushed surrounding rocks under unsymmetrical pressure in a section of Guangfu tunnel to improve the strength of surrounding rocks and arching effect of tunnel, high pressure pre-grouting technology with cement grouting and cement-silicate grouting from ground surface is proposed to reduce the groundwater permeability of the surrounding rocks, and to protect water resources and ensure the safety of construction. The treatment effect is analyzed by numerical simulation and field experiment. The comprehensive analysis shows that after grouting, integral degree and strength of surrounding rocks are improved and the velocity of convergence and crown settlement are increased. The deformation of tunneling is reduced; and the initial support and secondary lining mechanical behaviors are improved. The treatment of grouting is shown with good effect.