本文選題：瞬變電磁法 + 隧道超前地質預報�。� 參考：《廣西大學》2015年碩士論文

【摘要】：瞬變電磁法(TEM)是一種時間域地球物理探測方法,其廣泛應用于礦產(chǎn)勘探、災害預報和工程應用等領域。在隧道施工過程中,斷層、裂隙、溶洞等是常見的地質不良體,而這些不良地質體往往伴隨著大量的水體,如果在隧道開挖過程中沒有提前采取有效的預防措施,則可能引發(fā)突水突泥等地質災害的發(fā)生；由于瞬變電磁法對低阻體反映靈敏,水體相對隧道圍巖來說屬于低阻體,將瞬變電磁法引用到隧道超前地質預報成為近年的研究熱點。針對隧道不良含水構造的瞬變電磁響應特征和隧道突水突泥災害的瞬變電磁探測與預報進行了以下三方面的研究并取得了相當?shù)难芯砍晒?.采用Ansys電磁模擬軟件對各種復雜的地質模型進行了二維瞬變電磁正演,在充分分析模型參數(shù)的基礎上,完成了對隧道含水構造模型的構建和二維數(shù)值模擬并針對特殊構造分析了電磁響應特征,同時對瞬變電磁探測的整個反應過程進行視圖再現(xiàn)。數(shù)值模擬的主要成果如下：通過數(shù)值模擬實驗的結果可以看出,全空間和隧道空間的瞬變電磁響應差異主要集中在前期。低阻破碎帶模型中瞬變電磁響應的影響主要集中在：(1)破碎帶厚度越厚響應值越大；(2)破碎帶距離掌子面越近響應值越大；(3)破碎帶規(guī)模越大響應值越大；(4)破碎帶和圍巖的相對電性差異越大,其響應值相差越大。不同充實度的充水溶洞對瞬變電磁響應表現(xiàn)為：溶洞充實度越大,電磁響應值越明顯。2.根據(jù)相似性原理,選取合適的實驗材料,設計了物理模型實驗,對各種低阻地質體進行模擬并分析各瞬變電磁響應。主要成果如下：隧道空間的存在對探測結果有一定的影響,這個影響主要集中在對探測信號反應值大小的影響,對探測距離與探測反應值的衰減規(guī)律和反應出的現(xiàn)象影響不大。針對不同位置低阻體,電磁感應衰減曲線和多測道圖均顯示出一定的規(guī)律。模擬了金屬干擾的影響,結果顯示金屬干擾對探測結果影響很大,一般來說應該盡量掌子面后方存在大量的金屬干擾物或者金屬干擾物應該遠離掌子面。3.以岑溪大隧道和嶺腳隧道為依托,結合地質勘查報告和實際開挖記錄,對隧道突水突泥問題進行了預報,并引入了扇形探測新方法,預報結果和實際開挖結果相符,預報結果可信。
[Abstract]:Transient electromagnetic method (TEM) is a time-domain geophysical method, which is widely used in mineral exploration, disaster prediction and engineering applications. In the course of tunnel construction, faults, fissures and caverns are common geological bodies, which are often accompanied by a large number of water bodies, if effective preventive measures are not taken in advance in the course of tunnel excavation. Because the transient electromagnetic method is sensitive to the low resistivity body and the water body belongs to the low resistivity body relative to the surrounding rock of the tunnel, the application of the transient electromagnetic method to the advanced geological prediction of the tunnel has become a hot research topic in recent years. In this paper, the transient electromagnetic response characteristics of poor water-bearing structures in tunnels and the transient electromagnetic detection and prediction of tunnel water inrush and mud inrush disasters are studied in the following three aspects and a considerable research result: 1 is obtained. The 2-D transient electromagnetic forward modeling of various complex geological models is carried out by using Ansys electromagnetic simulation software. Based on the full analysis of the model parameters, The construction of tunnel water structure model and two-dimensional numerical simulation are completed, and the electromagnetic response characteristics are analyzed for the special structure, and the whole reaction process of transient electromagnetic detection is reproduced in view at the same time. The main results of numerical simulation are as follows: the results of numerical simulation show that the difference of transient electromagnetic response between the whole space and the tunnel space is mainly concentrated in the early stage. The effect of transient electromagnetic response in the low resistivity fracture zone model is mainly concentrated in: 1) the thicker the thickness of the broken zone, the larger the response value. (2) the larger the response value of the broken zone is to the palm surface, the larger the response value is. (the larger the scale of the broken zone is, the larger the response value is, the larger the response value is, the larger the response value is, the larger the response value is, the larger the response value is. The greater the difference in relative electrical properties of rocks, The larger the response value is, the greater the difference is. The transient electromagnetic response of water-filled caverns with different degree of enrichment is as follows: the larger the enrichment degree of the cavern, the more obvious the electromagnetic response value is. 2. According to the principle of similarity, the physical model experiments are designed to simulate and analyze the transient electromagnetic responses of various low-resistivity geological bodies by selecting suitable experimental materials. The main results are as follows: the existence of tunnel space has a certain influence on the detection results, which mainly focuses on the magnitude of the response value of the detection signal, but has little effect on the attenuation law of the detection range and the detection response value and the phenomenon of the response. For low resistive bodies at different positions, both the electromagnetic induction attenuation curve and the multi-track diagram show certain laws. The effect of metal interference is simulated. The results show that metal interference has great influence on the detection results. Generally speaking, there should be a large number of metal disturbances behind the face of the palm or metal interference should be far away from the face of the palm. 3. Based on the Cenxi big tunnel and Lingjiao tunnel, combined with the geological exploration report and the actual excavation record, the water inrush and mud inrush of the tunnel are forecasted, and a new method of sector detection is introduced. The prediction results are consistent with the actual excavation results. The forecast results are credible.
【學位授予單位】：廣西大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U452.11;P631.325

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本文編號：1790663