【摘要】：地應(yīng)力是地球內(nèi)部巖體屬性的重要參數(shù),是監(jiān)測(cè)地震、山體滑坡以及火山活動(dòng)的重要依據(jù)之一。為了實(shí)現(xiàn)對(duì)地下巖層空間應(yīng)力大小與方向的有效監(jiān)測(cè),基于光纖光柵傳感技術(shù)與平面應(yīng)力狀態(tài)測(cè)量原理,本文設(shè)計(jì)并研制出一種監(jiān)測(cè)地下空間應(yīng)力大小與方向的光纖光柵三維地應(yīng)力傳感器。地應(yīng)力傳感器采用各向異性碳纖維層積復(fù)合材料作為載體對(duì)光纖光柵進(jìn)行封裝,并將其做成應(yīng)變傳感單元;針對(duì)鉆孔監(jiān)測(cè)需求,三維地應(yīng)力傳感器整體結(jié)構(gòu)采用圓柱形結(jié)構(gòu)設(shè)計(jì),九個(gè)應(yīng)變傳感單元組成三組應(yīng)變花,每組應(yīng)變花分別放置于一個(gè)圓柱形監(jiān)測(cè)探頭上。三個(gè)探頭以一定的空間角度與機(jī)械結(jié)構(gòu)組裝成一體,形成了對(duì)地下空間應(yīng)力大小與方向監(jiān)測(cè)的光纖光柵三維地應(yīng)力傳感器。地應(yīng)力傳感器中的每個(gè)探頭分別監(jiān)測(cè)空間中的一個(gè)正交平面內(nèi)的應(yīng)力狀態(tài),將三個(gè)正交平面內(nèi)的最大主應(yīng)力進(jìn)行力學(xué)矢量合成,最終得到空間中最大主應(yīng)力的大小與方向。本文以光纖光柵傳感理論與應(yīng)變花測(cè)量平面應(yīng)力狀態(tài)原理為基礎(chǔ),將兩種理論知識(shí)相互結(jié)合并推導(dǎo)出最大主應(yīng)變與波長(zhǎng)變化之間的關(guān)系,給出光纖傳感技術(shù)應(yīng)用于地應(yīng)力測(cè)量的理論基礎(chǔ)。對(duì)應(yīng)變傳感單元進(jìn)行室內(nèi)溫度標(biāo)定實(shí)驗(yàn)與應(yīng)力加載實(shí)驗(yàn),溫度標(biāo)定實(shí)驗(yàn)結(jié)果:在24.1~55℃范圍內(nèi)的溫度系數(shù)平均值為57.3pm/℃;應(yīng)力加載實(shí)驗(yàn)結(jié)果:在0~60Mpa量程內(nèi)的應(yīng)力靈敏度為58pm/MPa,應(yīng)力分辨率為0.172MPa;線性擬合系數(shù)為0.99986。將三維地應(yīng)力傳感器埋置于水泥體中并進(jìn)行應(yīng)力加載實(shí)驗(yàn),傳感器應(yīng)力加載實(shí)驗(yàn)結(jié)果:S1、S2探頭的測(cè)量應(yīng)力大小平均相對(duì)誤差分別為16.31%、24.36%,方向誤差的平均值分別為1.89°、2.52°;S3探頭的絕對(duì)誤差為0.0068MPa。實(shí)際加載應(yīng)力與傳感器測(cè)量的應(yīng)力空間角度誤差平均值為1.24°。
[Abstract]:The in-situ stress is an important parameter of the earth's interior rock mass, and one of the important bases for monitoring earthquake, landslide and volcanic activity. In order to effectively monitor the spatial stress magnitude and direction of underground strata, based on the fiber grating sensing technology and the principle of plane stress state measurement, In this paper, a fiber Bragg grating three-dimensional in-situ stress sensor is designed and developed to monitor the magnitude and direction of stress in underground space. The in-situ stress sensor uses anisotropic carbon fiber laminated composite as carrier to encapsulate the fiber grating and make it into a strain sensing unit. According to the requirement of borehole monitoring, the whole structure of three-dimensional in-situ stress sensor is designed with cylindrical structure. Nine strain sensing elements are composed of three groups of strain flowers, each set of strain flowers is placed on a cylindrical monitoring probe. The three probes are assembled with the mechanical structure at a certain spatial angle, and a three-dimensional fiber grating in-situ stress sensor is formed to monitor the magnitude and direction of the stress in the underground space. Each probe in the in-situ stress sensor separately monitors the stress state in an orthogonal plane in space. The maximum principal stress in the three orthogonal planes is combined with mechanical vector, and the magnitude and direction of the maximum principal stress in the space are finally obtained. Based on the theory of fiber grating sensing and the principle of strain pattern measuring plane stress state, the relationship between maximum principal strain and wavelength change is deduced by combining the two theoretical knowledge with each other. The theoretical basis of the application of optical fiber sensing technology in-situ stress measurement is given. The indoor temperature calibration experiment and stress loading experiment of strain sensing unit were carried out. The results of temperature calibration experiment showed that the average temperature coefficient was 57.3pm/ 鈩，

本文編號(hào)：2455754