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1、 大跨度小净距公路隧道施工监测初探摘 要：随着我国高等级公路的飞速发展，由于特殊地质及地形条件的限制，出现了连拱隧道。针对连拱隧道施工的复杂工艺，衍生出一种新的结构形式，即小净距公路隧道。该种公路隧道跨度大，扁平率低，开挖多采用分部法，针对大跨度小净距公路隧道的围岩稳定性问题进行系统深入的研究具有重要的意义。完整地介绍了一整套大跨度小净距公路隧道施工监测方案。具有现实可实践操作意义。 关键词：大跨度小净距公路隧道；施工；监测 0引 言 近年来，现场量测与力学计算紧密配合，已形成了一整套监控设计的原理与方法，这种通过在隧道施工过程中所进行的现场量测获得围岩稳定性和支护系统工作状态的信息，然后将信
2、息反馈于施工决策和支护系统的设计过程称为“施工监测”，和“信息化设计”，包含施工监视的含义在内。这种方法因其适应地下工程的特点，能结合现场量测技术、计算机技术以及岩土力学理论、在铁路隧道、公路隧道和军事地下工程等工程领域得到了广泛的应用。 1目标大跨度小净距公路隧道施工概况 目标隧道采用平行双洞式，单洞净宽16m，洞高11.4m，呈北西-南东向展布，隧道里程K1710K2600，进洞口里程为K1710，设计进口路面高程363.220m，出洞口里程为K2600，设计路面高程357.20m，全长为890m，路面坡度0.7000 %。两洞侧壁间距6.959m。 目标隧道区段覆盖层厚0.002. 80
3、m。填筑土为软弱（场地）土，块石土及亚粘土属中软（场地）土，基岩为坚硬（场地）土。根据公路工程抗震设计规范（JGJ004-98）判断，隧道区场地类别为IIII类，属抗震有利地段。 隧道衬砌结构设计根据结构的受力特点采用复合式衬砌。在施工过程中要求按设计进行监控量测，并对量测信息进行处理、反馈，调整支护参数并贯穿于施工全过程。根据结构的受力特点，以锚杆湿喷钢纤维混凝土等为初期支护，以钢筋混凝土和钢纤维混凝土为二次衬砌，并根据不同的围岩类别，辅以超前中空注浆锚杆和工字钢拱架等辅助支护措施。 2大跨度小净距公路隧道施工监测目标与内容 2.1 监控量测的一般规定 （1）采用复合式衬砌的隧道，必须将现场
4、监控量测项目列入施工组织设计，并在施工中认真实施。 （2）量测计划应根据隧道围岩条件、支护类型和参数、施工方法以及所确定的量测目的进行编制。同时应考虑量测费用的经济性，并注意与施工进度相适应。 （3）监控量测应达到以下目的： 图2施工监测和信息化设计流程图 其一，掌握围岩和支护的动态信息并及时反馈，指导施工作业； 其二，通过对围岩和支护的变位、应力量测，修改支护系统设计。 （4）采用复合式衬砌的隧道、施工、设计单位必须紧密配合，共同研究，分析各项量测信息，确认或修改设计参数。 2.2 量测内容与方法 （1）复合式衬砌的隧道应按表1选择量测项目。表1中14项为必测项目；511项为选测项目，应根据
5、围岩条件、地表沉降要求等确定； （2）爆破后应立即进行工程地质与水文地质状况的观察和记录，并进行地质描述。地质变化处和重要地段，应有照片记载。初期支护完成后应进行喷层表面的观察和记录，并进行裂缝描述； 表1隧道现场监控测量项目及量测方法 注：B为隧道开挖宽度 （3）隧道开挖后应及时进行围岩、初期支护的周边位移量测、拱顶下沉量测。当围岩差、断面大或地表沉降控制严时宜进行围岩体内位移量测和其它量测； （4）量测部位和测点布置，应根据地质条件、量测项目和施工方法等确定； （5）测点应距开挖面2m的范围内尽快安设，并应保证爆破后24h内或下一次爆破前测读初次读数； （6）测点的测试频率应根据围岩和支护
6、的位移速度及离开挖面的距离确定； （7）现场量测手段，应根据量测项目及国内量测仪器的现状来选用。 3目标隧道施工监测方案设计 3.1监控量测项目及其目的 （1）地质及支护状况观察。对所选择的开挖面的岩性、岩层产状、结构面、溶洞、断层等工程地质和水文地质情况以及初期支护完成后喷层表面的裂缝状况进行观察和描述；预测开挖面前方的地质条件，并为判断围岩的稳定性提供地质资料；观测有无锚杆被拉脱或垫板陷入围岩内部现象，分析初期支护的可靠程度。 （2）隧道周边水平收敛和拱顶下沉量测。为判断隧道稳定性提供可靠信息；以围岩变位速率为二次衬砌提供合理的支护时机，利用量测信息的反馈，判断初期支护设计与施工方法是否稳
7、妥，从而达到修改设计和指导施工的目的。 （3）地表沉降。了解地表下沉的范围以及下沉量的大小、地表下沉量随工作面推进的变化规律、地表下沉稳定的时间。 （4）围岩内部位移量测。了解隧道围岩松弛区、位移量及围岩应力随深度的分布；了解围体内位移范围，判断锚杆长度是否适宜；为准确判断围岩的变形发展提供数据。 （5）锚杆轴力量测。了解锚杆受力状态，为确定合理的锚杆参数提供依据；判断锚杆布置是否合理以及评价锚杆的支护效果。 （6）衬砌应力的量测。了解喷层的变形特性以及喷层所受应力的大小，判断复合式衬砌中围岩荷载大小以及初期支护与二次衬砌各自分担围岩压力情况，量测二衬应力以及喷混凝土层内轴向应力，了解二次衬砌
8、的受力状态；判断喷层的稳定性和支护结构长期使用的可靠性以及安全程度。 3.2 监控量测断面的拟定 根据隧道工程地质情况和大跨度小净距隧道围岩与支护结构的受力特点，为满足隧道数据采集和保证施工安全，根据围岩类别与支护类型将其分为四种量测断面，分别为A型、B型、C型、D型。 A型量测断面（必测选测项目）：适用于隧道IV类围岩段、洞口段及破碎带。具体量测项目包括洞内地质与支护观察、净空变位及拱顶下沉、围岩内部位移、锚杆轴力、钢支撑应力、初期支护与围岩之间的压力、初期支护与二次衬砌之间的压力、爆破振动测试。 B型量测断面（必测部分选测项目）：适用于III类围岩。具体量测项目包括洞内地质与支护结构观察、
9、净空变位及拱顶下沉、围岩内部位移、锚杆轴力、初期支护与围岩之间的压力、初期支护与二次衬砌之间的压力、爆破振动测试。 C量测断面（全必测项目）：适用于隧道各类围岩段。具体量测包括：洞内地质状态与支护结构安全性观测、净空变位及拱顶下沉。 D型断面量测（仅爆破振动测试）：D型断面为振动波测试，适用于隧道各类围岩段。设置该量测断面的目的是为了测试后行洞在爆破中对先行洞的影响。 3.3 量测方法和测点布置 （1）地质状况素描。对新开挖断面的岩性、岩层产状、结构面、断层等工程地质和水文地质情况以及初期支护完成后喷层表面的裂缝状1况进行观察和描述。同时观测有无锚杆被拉脱或垫板陷入围岩内部现象，锚杆和喷层有无
10、施工质量问题。 （2）水平收敛及拱顶下沉量测。在确定量测的新开挖的断面拱顶及轴线左右设3个带挂钩的锚桩，测桩埋设深度30厘米，用快凝水泥或早强锚固剂固定，测桩头设保护罩。用收敛计量测铜壁收敛位移。 （3）地表沉降观测。在选定的量测断面区域，先设置一个通视条件较好、测量方便、牢固的基准点。测点布置在隧道轴线及其两侧，每个断面根据实际情况设共711个测点。测量范围为隧道底两侧向上45度与地表相交，测点埋设水泥桩，用红色油漆做标记，并予以编号，用精密水准仪测量。 （4）围岩内部位移及锚杆轴力量测。根据围岩岩性实际情况，在隧道选取10个断面，每个断面在拱顶、拱腰、拱脚打5个测孔，孔深3.75米，孔径5
11、060。每个测孔内设4个测点并安装上传感器，每个断面一共20个测点。用千分表读取位移，用钢筋计量测轴力。 （5）初期支护与围岩之间应力、二次衬砌之间应力量测。沿隧道周边拱顶、拱腰埋设传感器，将压力盒分别埋设在围岩与喷射混凝土之间、喷射混凝土与二次衬砌之间。围岩与喷射混凝土之间的应力盒在喷射混凝土之前埋设，喷射混凝土与二次衬砌之间的应力盒在挂防水板之前进行安装。 3.4 量测频率和时间 对于每一断面，在量测初期应予以实时监控，待应力、应变逐步稳定后可降低量测频率。 3.5 数据采集及仪器装备 现场监控量测工作人员根据规范和监控量测计划规定的频率坚持每天到洞内采集数据，并将采集的数据及时绘出或输入
12、计算机进行处理，如果发现量测数据出现异常变化，则及时分析引起变化的原因，使问题能得到有效处理。 监控量测仪器及主要传感器如下：精密水准仪、全站仪、振弦频率监测仪、隧道收敛计、百分表、锚杆测力计、压力盒、爆破振动自记仪、机械式多点位移计、地质罗盘、温度计、速度传感器（水平、垂直）等。 3.6 量测断面的选择 共埋设45个断面，其中有3个A型断面、5个B型断面、35个C型断面、2个D型断面，并进行了地质调查、水平收敛、拱顶下沉、围岩内部位移、锚杆轴力、围岩接触应力、爆破振动测试等方面的监控量测。 4小结 首先，隧道在开挖期间围岩水平收敛、拱顶总沉降量和围岩变形速率都在规范要求的范围内，而且围岩的变
13、形最终都趋于稳定； 其次，围岩内部位移随着测点深度的增加，围岩相对位移明显减少；中夹岩柱处的围岩松动圈最大，接近3.5m，围岩稳定性差。隧道进口段地表沉降在隧道拱顶正上方的地面沉降最大，而且左洞对应的地表沉降明显大于右洞，说明右洞的开挖对左洞的地表沉降有明显的影响； 然后，中夹岩柱处的锚杆轴力最大，在中夹岩柱处，锚杆起到了很好的锚固效果，对围岩的稳定起到了很重要的作用。接触应力一般在拱顶相对较大，而两侧的拱腰压力则较少，围岩与混凝土衬砌粘结密室。 最后，设计方协商变更设计、施工，尤其要注意围岩中的水对围岩稳定性的影响，应及时进行疏导、排除。 参考文献 1公路隧道设计规范S.JTG D70-20
14、04 2万明富.隧道围岩净距讨论与小净距隧道研究M.北京：人民交通出版社，2005. BRorganization system and working mode, the selection of a number of municipal strengthening group to build innovation and strengthen the organization of the basic level organizations advanced model.(seven) the manual work of the Communist Youth League Orga
15、nization published and League branch of manual work, to promote the use of two manuals in the citys organizations at various levels. The county committee, directly under the group (work) is under the jurisdiction of grassroots League and group (total) using branch ratio shall not be less than 70%.Th
16、ree, to further strengthen the groups leadership and team building(a) to strengthen the leagues leadership at all levels of construction. Continue to do a good job of municipal Party Committee Organization Department on the strengthening of the Communist Youth League cadres management opinions imple
17、mentation. To promote the group counties (autonomous counties, cities) Commission and city directly under the group (workers) appointed to carry out the Five team building activities. Improve the League Association Department working mechanism. Conscientiously fulfill the duties of CO, combined with
18、 the city group directly under (the) Committee of the general election and the adjustment, actively jointly with the unit where the party organization department good group leadership selection with the work. Do a good job in municipal Party committee assistant committee leadership and leading cadre
19、s of the annual assessment work, adhere to and improve the assistant secretary of the Communist Youth League talk system group To weave individual conversation and collective conversation, to strengthen the committees of all levels, the Standing Committee of the Standing Committee, the establishment
20、 of a sound system of central group learning, the system of investigation and study, the system of important issues and the reporting system.(two) to strengthen the work of education and training of cadres to conscientiously implement the Central Committee. On the implementation of grassroots cadres
21、 training project and opinions on carrying out the mission municipal CYL Cadres training project implementation opinions, full implementation of the project of the City Youth League cadres training education. Focus on the county grassroots cadres and workers focused on training, the new school syste
22、m vocational training League cadres, for the Municipal Organization Department jointly held the third session of the Communist Youth League system training cadres in party. Focusing on the construction of new socialist countryside, strengthening village cadres and rural construction team group membe
23、r of the young team, the county organizations at various levels throughout the year is expected to train 100 00 rural grassroots cadres, plans to train 1000 village secretary of the village Party branch.(three) actively promote grassroots cadres election work. Under the unified leadership of the par
24、ty organization, to strengthen grassroots organizations direct work, standardize the election work rules and procedures, in the designated candidate, open competition to democratically elected branch secretary at the same time, actively and steadily the development of Township, streets and other gra
25、ssroots organizations in the direct election of the pilot work, on the basis of summarizing the experience and gradually expand the scope of the pilot, and gradually formed a set of measures and cadres election system.(four) to strengthen the cadres testing exercise. To study the development of XX c
26、ity from 2006 to 2008 cadres testing exercise planning. To select outstanding cadres to the central mission in Beijing, Shanghai, Guangzhou and other central organs and sending work in developed areas. With the Central Committee the implementation of the western region and ethnic minorities cadres t
27、raining plan . To carry out the eighth batch of municipal organs attachment cadre management, selection, training work. The outstanding cadres to start the National Development Bank XX branch testing exercise.(five) to strengthen the group construction. The main position to play the role of Youth Le
28、ague cadre education and training as the city, in accordance with the requirements of post training, further curriculum scientifically and rationally, adopt arrangement menu course, basic theory includes group work, focus, hot and difficult issues, to enhance the content and practice; to strengthen
29、the construction of teaching staff, the integration of teachers, establish a quality teacher training team, establish and implement course evaluation system; take delivery of training to the countryside, on-site training, and increase the rural grassroots cadres training efforts.Four, efforts to str
30、engthen the work of young talent(a) to tenth XX young 54 medal in recognition of the publicity, and actively explore the XX youth service. 54 Medal of institutionalization, standardization and socialization mechanism. Give full play to the XX award in recognition of 54 youth medal Association, Youth
31、 Award winner in the 54 chapter, investigation activities. Who won the Youth Service medal, dedication to the society to create conditions, build the stage. During the 54, named in recognition of the tenth XX young 54 medal. The association of XX editing of young talent , the exchange of information
32、 and communication platform for the XX of outstanding young talents.(two) the establishment of municipal Party committee of young talent information database. In accordance with the feasible, effective, classification management, implement step by step principle, the establishment of municipal Party
33、 committee of youth talent database; guiding organizations at various levels generally established the young talent database, construction of city, county (directly under the Communist Youth League), grassroots organizations three young talent information database the relevant information collection
34、 system, and gradually establish the citys young people, the Communist Youth League youth talent information network, provide information platform for young talent resource development.Five, take effective measures to strengthen the mission management(a) to strengthen the mission management work. St
35、rengthen the dues collection and management, continue to adhere to the dues collection regularly reporting system, the annual comprehensive award in recognition of the tour and the tour one vote veto system audit system. Do statistical work in the group. The group service award in recognition of the
36、 advanced units, standardization, promoting group management work institutionalized.(two) to strengthen the organization of research and information exchange efforts. Grassroots carry out research, efforts to form a number of theoretical results. Make full use of the network carrier, to explore the
37、establishment of electronic group service system, promote the work of Communist Youth League information.Attachment 4:XX municipal Party Committee Propaganda Department of the Communist Youth League work pointsIn 2006, the Communist Youth League propaganda ideological work XX to Deng Xiaoping theory
38、 and the important thought of Three Represents as guidance, study and implement the partys sixteen and the spirit of the the fifth Plenary Session of the 16th CPC Central Committee implementation of the eight plenary session of the two committee, the citys cultural work conference, the Propaganda De
39、partment of the meeting and the the fourth Plenary Session of the 15th CPC Central Committee permanent mission spirit, closely around 11th Five-Year XX the goal of full implementation of Scientific Outlook on Development, emancipating the mind, seeking truth from facts, keep pace with the times, clo
40、se to reality, close to life, close to the young, persevere grasp orientation, grasping deepening, grasping construction innovation, further improve the groups propaganda and ideological work ability, unity To guide the majority of members of the youth to achieve the 11th Five-Year planning tasks, t
41、he overall construction of a well-off society, building a socialist harmonious society to make new contributions.One, adhere to the Three Represents important thought and Scientific Outlook on Development education to guide the youth, to further strengthen the ideological and political education of
42、youth(a) armed with youth science theory. Unremittingly with Deng Xiaoping theory and the important thought of Three Represents armed members of youth education, to promote the study and implement to expand the depth and breadth. To study and implement the important thought of Three Represents with
43、the establishment and implementation of Scientific Outlook on Development combine with the implementation of the requirements of constructing socialist harmonious society with Scientific Outlook on Development, carry out education as an important part of the theory of armed youth in the new period,
44、strengthen the establishment and implementation of Scientific Outlook on Development education, educate and guide the youth to fully understand the great significance of establishment and implementation of Scientific Outlook on Development, in-depth understanding of the Scientific Outlook on Develop
45、ment era back The king, the practice foundation, basic connotation, historical status, spirit and practice requirements, a profound understanding of Scientific Outlook on Development with Marxism Leninism, Mao Zedong thought, inheriting and developing relationship between Deng Xiaoping theory and th
46、e important thought of Three Represents, to help young people establish and consciously practice Scientific Outlook on Development. Persist in learning, grasping the backbone, grasp the practice, grasp the opportunity. Catch club, effective way to grasp the network, with the group of cadres, young s
47、tudents and young backbone fronts as the focus, to promote the work of the armed youth theory to develop in depth, to help the youth continue to firm ideals and beliefs, to build a powerful spiritual pillar. To carry out the study and implementation of the partys sixteen session of the five Eight pl
48、enary session of the two plenary session of the Central Committee and the party spirit, to the citys Youth League members thinking into the spirit of the meeting, to achieve the goal of national consciousness and XX economic and social development in 11th Five-Year period. Contribute to help and guide the youth to a profound understanding of the significance and main task of building a socialist harmonious society, acti
