围岩快速分级和松动圈测试应用研究

吉图珲客运专线小盘岭1#~3#隧道施工,遇到碳化泥质板岩地层,由于其岩质软、节理发育、岩体破碎,围岩稳定性极差,多次发生塌方、换拱等问题。为保证隧道安全快速施工,现场采用非金属声波测试技术对围岩进行施工期快速分级和松动圈厚度确定,为隧道动态设计和信息化施工提供有力保障。(1)声波测试结果分析表明,该隧道碳化泥质板岩松动圈厚度范围在4.90~6.16 m之间;左拱腰、拱顶和右拱腰位置松动圈厚度均值分别为5.91 m、5.35 m和5.19 m。(2)围岩饱和单轴抗压强度为20.6 MPa,属于软质岩;松动圈内围岩波速平均值为1.29 km/s;松动圈外围岩波速平均值为2.06 km/s。综合判定小盘岭隧道弱~强风化碳化泥质板岩围岩等级为Ⅴ级,与现场调查结果基本一致。基于测试结果对隧道支护锚杆和注浆长度进行优化,工程实践表明优化后的锚杆支护和注浆加固效果明显。

Application Research on Rapid Surrounding Rock Classification and Loose Circle Test

During the construction of Xiaopanling 1#~3#tunnel of Jilin-Tumen-Hunchun passenger dedicated line,carbonized argillaceous slate stratum was encountered,due to its soft rock,joint development,rock mass fracture,poor stability of surrounding rock,frequent collapse,arch replacement,etc.In order to ensure the safe and rapid construction of the tunnel,the non-metallic acoustic testing technique was carried out on the site,the rapid classification of the surrounding rock during the construction period and the determination of the thickness of the loose circle were carried out,which could provide a strong guarantee for the dynamic design and information construction of the tunnel.(1)The acoustic testing results shows that the thickness of the loose circle of the tunnel carbonized argillaceous slate is between 4.90 m and 6.16 m.The average thickness of loose circle at left hance,vault and right hance is 5.91 m,5.35 m and 5.19 m,respectively.(2)The saturated uniaxial compressive strength of surrounding rock is 20.6 MPa,belonging to soft rock.The average wave velocity of surrounding rock interior and exterior loose circle is 1.29 km/s and 2.06 km/s,respectively.Comprehensive judgment of the weak~strong weathering carbonized argillaceous slate in Xiaopanling tunnel is V grade surrounding rock,and field survey results are consistent.Based on the test results,the supporting bolt and grouting length of the tunnel has been optimized.Engineering practice shows that the effect of bolt support and grouting reinforcement after modification is obvious.