高水压岩质盾构隧道二次注浆压力的控制

Study on the Control Pressure of Secondary Grouting for Shield Tunnel in Rock under High Water Pressure

采用梁—弹簧模型模拟盾构隧道管片衬砌结构,针对不同的二次注浆方式,包括注浆孔的布置、充填空隙的长度和注浆压力,进行力学分析。结果表明:不同注浆方式下管片结构的力学特征不同,在注浆压力及所填充空隙长度相同的条件下,不对称注浆对管片结构的受力最不利;在注浆方式相同、注浆压力和所充填空隙长度不同的条件下,管片结构的内力和变形形状相同,但内力和变形的大小不同,随着注浆压力和所充填空隙长度的减小,管片结构的内力和变形减小。在岩质盾构隧道施工中,二次注浆所充填的空隙长度是不确定的,故从安全出发,最大二次注浆压力应控制在0.6 MPa以内,注浆压力的下限值可由能注入浆液进行控制。

The internal forces and deformation of the segment lining were analyzed under different grouting modes, which were involved with the location of secondary grouting hole, grouting space length and grouting pressure, beam-spring model was used as simulating the segment lining in the calculation. The results show that the mechanical behaviors of the segment lining under different grouting modes are dissimilar, the segment lining loaded asymmetry grouting stands in the worst mechanics state. The internal forces and the deformation of segment lining decrease with the diminishment of secondary grouting pressure and grouting space length. The grouting space length is indefinite in the construction of shield tunnel in rock. So taking safety into consideration, the control pressure of secondary grouting is less than 0. 6 MPa, and lower limit of secondary grouting pressure is controlled with being able to inject grouting material.