岩土工程学报
巖土工程學報
암토공정학보
CHINESE JOURNAL OF GEOTECHNICAL ENGINEERING
2015年
4期
711-717
,共7页
刘宗辉%吴恒%周东%韦鸿耀
劉宗輝%吳恆%週東%韋鴻耀
류종휘%오항%주동%위홍요
隧道衬砌%探地雷达%频谱反演%脱空高度%二衬厚度
隧道襯砌%探地雷達%頻譜反縯%脫空高度%二襯厚度
수도츤체%탐지뢰체%빈보반연%탈공고도%이츤후도
tunnel lining%ground penetrating radar (GPR)%spectrum inversion%void area height%second lining thickness
隧道衬砌模型的空间结构属于典型的层状分布,采用探地雷达进行隧道二衬检测时,往往很难识别高度小于调谐厚度的脱空。通过建立含有脱空薄层的隧道二衬层状几何模型,结合电磁波在隧道衬砌中的传播规律,给出了隧道衬砌检测时电磁波的反射模型,并推导了其广义反射系数谱域表达式,从而提出一种根据反射系数序列频谱估算隧道二衬厚度及脱空高度的反演方法。通过分析反射系数序列的幅度谱属性,进一步提出一种估计脱空层高度的快速方法,即根据幅度谱凹陷周期确定脱空层双程走时,进而估算脱空层高度。最后,利用1stOpt 数学优化分析软件进行全局优化,并反演求解各参数。物理模型实验及现场应用实例的处理结果表明,当脱空厚度小于1/4波长时,本文所述的频谱反演法仍能准确反演出二衬厚度及脱空层高度,从而提高了探地雷达资料的垂直分辨率。
隧道襯砌模型的空間結構屬于典型的層狀分佈,採用探地雷達進行隧道二襯檢測時,往往很難識彆高度小于調諧厚度的脫空。通過建立含有脫空薄層的隧道二襯層狀幾何模型,結閤電磁波在隧道襯砌中的傳播規律,給齣瞭隧道襯砌檢測時電磁波的反射模型,併推導瞭其廣義反射繫數譜域錶達式,從而提齣一種根據反射繫數序列頻譜估算隧道二襯厚度及脫空高度的反縯方法。通過分析反射繫數序列的幅度譜屬性,進一步提齣一種估計脫空層高度的快速方法,即根據幅度譜凹陷週期確定脫空層雙程走時,進而估算脫空層高度。最後,利用1stOpt 數學優化分析軟件進行全跼優化,併反縯求解各參數。物理模型實驗及現場應用實例的處理結果錶明,噹脫空厚度小于1/4波長時,本文所述的頻譜反縯法仍能準確反縯齣二襯厚度及脫空層高度,從而提高瞭探地雷達資料的垂直分辨率。
수도츤체모형적공간결구속우전형적층상분포,채용탐지뢰체진행수도이츤검측시,왕왕흔난식별고도소우조해후도적탈공。통과건립함유탈공박층적수도이츤층상궤하모형,결합전자파재수도츤체중적전파규률,급출료수도츤체검측시전자파적반사모형,병추도료기엄의반사계수보역표체식,종이제출일충근거반사계수서렬빈보고산수도이츤후도급탈공고도적반연방법。통과분석반사계수서렬적폭도보속성,진일보제출일충고계탈공층고도적쾌속방법,즉근거폭도보요함주기학정탈공층쌍정주시,진이고산탈공층고도。최후,이용1stOpt 수학우화분석연건진행전국우화,병반연구해각삼수。물리모형실험급현장응용실례적처리결과표명,당탈공후도소우1/4파장시,본문소술적빈보반연법잉능준학반연출이츤후도급탈공층고도,종이제고료탐지뢰체자료적수직분변솔。
The spatial structure of tunnel lining model is a typical stratiform distribution, so it is difficult to identify the void area if its height is less than tuning thickness when using ground penetrating radar (GPR) to detect the second lining of tunnel. In this paper, by establishing a geometrical model for the second lining layer of tunnel including void area and considering the spreading law of electromagnetic waves in tunnel lining, a reflection model for electromagnetic waves in tunnel lining detection is obtained, and the generalized reflection coefficient in spectrum expression is deduced as well as an inversion method to further estimate the lining thickness of tunnel and the height of void area according to the reflection coefficient sequence spectrum. By analyzing the amplitude spectrum properties of the reflection coefficient sequence, a quick method to estimate the height of void area is proposed, namely determining the two-way travel time of void area and leading to the height of void area according to the depressing period of the amplitude spectra. Finally, 1stopt mathematical optimization analysis software is adopted for the global optimization and calculation of parameters. The results of physical model experiments and field tests indicate that the spectrum inversion method can also estimate the lining thickness of tunnel and the height of void area accurately when the height of void area is less than 1/4 wavelength, consequently enhancing the vertical resolution of GPR data.