地质雷达在风火山隧道病害检测中的应用与结果分析

DETECTION AND ANALYSIS OF TUNNEL DEFECTS WITH GEOLOGICAL PENETRATING RADAR AT FENGHUO MOUNTAIN

青藏铁路全线开通运营以来,对处于高寒地区的永久冻土隧道之一的风火山隧道的质量状态首次进行了无损检测。风火山隧道处于高寒永久冻土区,隧道全部处于冻岩中,两端洞口主要为砂岩与泥岩,并且为富冰冻土。受到季节性冻融的影响,隧道病害比较突出,主要表现为衬砌裂缝,漏水涌水,衬砌酥松剥落。为了准确地掌握风火山隧道衬砌结构质量状态,本文首次应用于风火山隧道衬砌结构的质量检测。该检测设备一改传统破坏式的检测方法,具有快速、简捷、无损、灵活的特点。通过对现场数据处理分析,可以精确探测衬砌厚度,查明衬砌背后存在的空洞和回填不密实区域。检测结果表明,隧道在高寒恶劣环境中,衬砌总体外观质量尚好,但是在两端洞口段有渗水现象;衬砌背后空洞缺陷等级为严重地段测线长度为20m,等级为极严重地段测线长度为98m;衬砌背后回填不密实缺陷等级为严重地段测线长度为41m,等级为极严重地段测线长度为33m。检测结果与实际病害情况基本相符。

The soundness diagnosis testing was carried out on the quality state of a tunnel at Fenghuo Mountain tunnel.This tunnel is one of the permafrost tunnels in frost soil area along the Qinghai-Tibet Railway line.The testing was done some years later after the railway was used.The tunnel is in alpine permafrost zone.The tunnel body is in the frozen rocks.At both ends of the tunnel,the dominant rocks are sandstone and shale,where the frozen soils are ice-rich.Due to the seasonal effects of freezing and thawing,defects were appear in the tunnel more and more.The defects are manifested mainly as lining cracks,leaking and gushing water,lining crisp peeling.In order to accurately understand the quality state of the tunnel lining,the geological penetrating radar technique was used to defect and quantify the defects in the tunnel field.The technique was applied to the tunnel lining structure quality inspection.The technique changed the traditional destructive testing method.The technique is fast,simple,non-destructive,and accurate.Through the in-situ data processing and analysis,the technique can accurately detect lining thickness,find out of lining and filling the empty space behind the non-dense area.The test results show the following.The tunnel in the frozen atrocious weather environment,the lining appearance was not damaged.Seepage was found in the openings of two ends.The lining with empty is the most serious defect level and had a measured length of 20m.The line with the secondary serious defect level had a length of 98m.The lining backfill behind the non-compact class is the third serious defect level and has a measured length of 41m.The most serious level has a line length of 33m.Test results are basically consistent with the actual defect situation.The results can provide a scientific basis for normal operation of the tunnel and reliable foundation for defect treatment in the future.Practical evidence proved the use of geological penetrating radar to make health diagnostic tests for the tunnel is feasible.