公路交通技术
公路交通技術
공로교통기술
TECHNOLOGY OF HIGHWAY AND TRANSPORT
2015年
1期
94-97
,共4页
公路隧道%现场监测%锚杆轴力
公路隧道%現場鑑測%錨桿軸力
공로수도%현장감측%묘간축력
highway tunnel%site monitoring%axial force of anchor rod
由新奥法隧道设计理论可知,锚杆是通过其轴向拉力来实现对围岩的加固作用的,也就是说锚杆发挥其锚固作用是利用其抗拉特性。为了深入了解高速公路大跨度隧道锚杆的实际受力特征,以邢汾高速公路邢台段某隧道为例,对其Ⅳ级围岩深埋段选定一处典型监测断面,采用现场监测的手段对锚杆的受力状态进行监测。监测结果显示:3根测力锚杆在其内部的大部分测点均承受压力。这一监测结果与理论上锚杆受拉完全相反,锚杆承受压力是不能发挥支护作用的;其余少数测点承受拉力,最大实测拉力约为7 kN,该值仅占到锚杆可承受最大设计拉力92 kN的7.6%。可以认为,某隧道在该监测断面处系统锚杆发挥的抗拉性能极其有限,几乎起不到应有的支护作用,这对修改现有隧道围岩支护设计规范提供了数据支持。
由新奧法隧道設計理論可知,錨桿是通過其軸嚮拉力來實現對圍巖的加固作用的,也就是說錨桿髮揮其錨固作用是利用其抗拉特性。為瞭深入瞭解高速公路大跨度隧道錨桿的實際受力特徵,以邢汾高速公路邢檯段某隧道為例,對其Ⅳ級圍巖深埋段選定一處典型鑑測斷麵,採用現場鑑測的手段對錨桿的受力狀態進行鑑測。鑑測結果顯示:3根測力錨桿在其內部的大部分測點均承受壓力。這一鑑測結果與理論上錨桿受拉完全相反,錨桿承受壓力是不能髮揮支護作用的;其餘少數測點承受拉力,最大實測拉力約為7 kN,該值僅佔到錨桿可承受最大設計拉力92 kN的7.6%。可以認為,某隧道在該鑑測斷麵處繫統錨桿髮揮的抗拉性能極其有限,幾乎起不到應有的支護作用,這對脩改現有隧道圍巖支護設計規範提供瞭數據支持。
유신오법수도설계이론가지,묘간시통과기축향랍력래실현대위암적가고작용적,야취시설묘간발휘기묘고작용시이용기항랍특성。위료심입료해고속공로대과도수도묘간적실제수력특정,이형분고속공로형태단모수도위례,대기Ⅳ급위암심매단선정일처전형감측단면,채용현장감측적수단대묘간적수력상태진행감측。감측결과현시:3근측력묘간재기내부적대부분측점균승수압력。저일감측결과여이론상묘간수랍완전상반,묘간승수압력시불능발휘지호작용적;기여소수측점승수랍력,최대실측랍력약위7 kN,해치부점도묘간가승수최대설계랍력92 kN적7.6%。가이인위,모수도재해감측단면처계통묘간발휘적항랍성능겁기유한,궤호기불도응유적지호작용,저대수개현유수도위암지호설계규범제공료수거지지。
As shown from tunnel design theory of the New Austrian Tunneling Method , anchor rods realize the effect of reinforcing wall rocks via axial tensile force , that is, anchor bolts develop their anchor role by means of tensile characteristics .For deep understanding of the actual mechanical features of anchor rods in large-span tunnels on expressways , this paper , with some tunnel at Xingtai section of Xingtai -Fenyang Expressway as an example , selects a typical monitoring section from deeply buried sections of grade IV wall rock to monitor the stress state of anchor rods by means of site monitoring .The monitoring result shows that most of measured points inside the 3 load anchor rods bear pressure .This monitoring result is completely opposite to the tension of anchor rods in theory , and anchor rods under the pressure cannot develop supporting role;the other few measured points bear tension and the max .measured tension is approximate 7 kN, which only accounts for 7.6% of the maximum.design tension 92 kN that anchor rods can withstand .It can be regarded that the tensile performance that system anchor rods develop at the monitoring section of the tunnel is extremely limited and hardly plays the due supporting role , this can provide data support for modifying the existing code for design of wall rock support of tunnels .