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1、【精品文档】如有侵权,请联系网站删除,仅供学习与交流s公路沥青混凝土路面平整度及纵横向裂纹的影响因素分析.精品文档.公路沥青混凝土路面平整度的影响因素分析摘要:本文是通过我在一条路面材料为沥青混凝土的公路一年的施工实践总结和对正在使用不久的的几条沥青混凝土路面公路平整度及预防纵横向裂缝的认识及对这几条公路、沥青混合料的拌合、摊铺、碾压摊铺等多方面进行了详细 调查并细致的分析了影响沥青混凝土路面平整度的施工因素和如何预防裂缝。并在老前辈已经分析出来的因素和相应的的解决方法的基础上加以补充,提出了相应的对策为指导沥青混凝土路面施工提供了参考。关键词:路面平整度;公路;沥青混凝土路面及纵横向裂缝随着
2、人们生活质量的提高,对出行行车舒适的要求也越来越高。在不同材料的路面中,由于沥青混凝土路面具有较好的行车舒适性、低的扬尘性及耐磨抗滑低噪声,维修方便等特点。因此,沥青混凝土路面越来越多的被应用在高速公路和普通干线公路上。沥青混凝土路面的平整度是评定路面质量和使用性能的主要指标之一,良好的平整度能有效的保证车辆高速、舒适、安全地行车。在工程竣工验收时,路面的平整度又是评价高速公路施工质量的重要参数之一。公路等级越高,对路面平整度的要求就越高。路面平整度,不但直接关系到行车的安全、舒适,还会影响车辆的燃料消耗,轮胎磨损、运输时效及其它经济、环保指标。而且路面的不平整会直接导致车辆对路面的冲击、车辆
3、振动,这样既不利于行车安全同时又加速了路面的损坏。影响沥青混凝土路面平整度的因素有很多,施工过程的每一个环节甚至微小失误都会造成平整度指标降低。下面主要从沥青混凝土路面施工的机械配置、施工工艺等方面对影响沥青路面平整度因素作一简要分析并提出相应解决对策。第一章 路面平整度的概念路面平整度是路面表面诱使行驶车辆出现振动的高程变化(其纵向起伏的波长范围约为0.550m),它可以用仪器进行量测。而乘客对振动的感受和接受能力带有主观性,往往采用小组评分的方法进行主观评定。 路面使用初期的平整度与施工技术水平(工艺和设备)、施工生产质量控制、面层构造(如接缝)和材料(如集料粒径)等因素有关。而在使用期间
4、,随着车辆荷载的反复作用、周围环境周期变化的影响以及路面龄期的增加,路面的平整度会随着各种路面病害的出现而逐渐下降。当平整度下降到一定的期限时,路面便不能满足基本功能的要求,而需采取适当的改建措施以恢复其功能。第二章 公路沥青混凝土路面平整度影响原因及纵横向裂缝是怎样形成的沥青混凝土路面不平整及纵横向裂缝是怎样形成的原因根据施工机械的配置和施工工艺的分析,造成沥青混凝土路面不平整或平整度下降的原因是多方面的,其主要原因有以下几方面:第一节 路基下沉对沥青混凝土路面平整度和纵横裂缝的影响及处理办法路基下沉主要表现在公路建成通车后,路基在自身重力及行车荷载作用下而发生的路基沉降,其主要由路提固结沉
5、降和地基沉降两部分及组成。路基是路面的基础,路基不均匀沉降必然会引起路面的纵横向列缝不平整。由于公路地基的地质情况变化较大以及各路基施工单位工程施工质量的差异,不可避免地会造成路基完工后发生不均匀沉降,从而造成路面变形起伏使平整度差。以多条公路沥青路面的使用经验证明:路基不均匀沉降引起的路面裂缝及沉陷往往最大,导致上面的路面裂缝及不平整度也往往最严重。路基不均匀沉降是指路基表面在垂直方向产生较大的沉落。它的沉降可以有三种情况,一是路基本身的压缩沉降;二是由于路基天然地面承载力不足,三是台背回填因为施工不当容易引起横向裂缝或错台,在路基自重作用下一起沉陷或向俩侧挤出而造成。路基的沉缩是因为路基填
6、料选择不当,填筑方法不合理,压实度不足在路基堤身内部形成过湿的夹层等因素在荷载和水温综合作用下引起路基沉缩。沥青混凝土路面的开裂表现有多种形式,如纵向、横向网状等。若不能及时处理,往往会造成路面渗水、扩展及路面损坏。它是地基上增加荷载而引起的沉降。根据沉降的不同情况采取不同的措施进行处理。目前已有许多较成熟的处理措施,实际采取何种措施,一般要因地制宜区别对待。软层较浅及厚度较小或面积不大的地基,可采用挖除换土法彻底处理;在工期短来不及提前试验,也没有足够的沉降期,可采用加强、加固及复合法处理,地基沉降不均匀,旧路改造拓宽工程,新旧路基、路面的搭接部位没有严格做好开台阶分层压实处理,以及下部基层
7、柔软,土层处理不彻底,引起路基路面纵向开裂。可采用分层填筑,边坡充分压实,用重型压实标准。旧路加宽或半填半挖地段:路基填筑前应将边坡松土清除并按填土厚度进行开蹬处理并压实。横向裂缝应采取防裂措施,及时对基层养生以减少前期开裂及时铺筑沥青面层或浇洒透层油以减少裸露时间,减少基层横向干缩性开裂。3.1.2路提固结沉降及纵横向裂缝的产生的主要原因是由施工引起的。如施工的路基填土干容重标准代表性差,取土样不规范,做压实度检测时有误差,压实度检测的代表性以及规范规定的检测频率不高等因素。采取的处理方法,一是按试验规程严格试验,取消人为的误差;二是加大检测频率;三是提高压实标准,在原设计的基础上提高一个级
8、区。这些措施在公路的使用取得了较为理想的效果。3.2路面基层对沥青混凝土路面平整度的影响基层的平整度对路面平整度有着重要影响。若基层不平即使面层摊铺平整,压实后也会因虚铺厚度不同产生路面不平整。对于沥青路面因基层顶面的平整度允许偏差为10mm,当用沥青混凝土摊铺机作业时,尽管沥青混合料表面是摊平了,但因该处多出10mm的松铺厚度压实后仍将出现低洼。在路面的施工中虽然可以弥补,但其层的平整度太差,必然会使面层的平整度受到影响。因为基层标准不高,凹凸过多过大,会导致摊铺机两条履带在分别不规则的高低面上行驶,从而使熨平板两端部出现波浪。3.2.1要重视路面的各层平整度路面结构层是层状的结构体系,一般
9、由面层、基层和垫层构成。在路面结构中,下承层的平整度直接影响着上一面层平整度的好坏。沥青混凝土面层的各层厚度一般只有4.08.0厚。虽然通过各层结构层的铺筑可减少下承层平整度的不良影响,但不可能完全调整下承层的不平整。因此在以往工地施工中流行着“基层不平面层调,下层不平上层找”的老方式是十分错误而有害的。总之,保证下承层的平整度和确保下承层上层的预压实厚度的均匀性是确保沥青沥青混凝土面层具有良好平整度的先决条件。在路基面层施工过称中采用具有自动找平装置的基层摊铺机进行基层混合料摊铺是必须强调的硬性规定。为了防止混合料的离析,要进行路面底基层、基层厂拌水泥稳定粒料的检查。加强松铺、压实面的高程、
10、横坡、平整度控制。尽可能使下承层顶面平整、密实,满足设计的高程和横坡。对公路路面各层都必须抓平整度,越往上要求的标准越高,最终才有可能达到理想的平整度。现在的高速公路施工混合料均匀所以表面平整,且高程、纵横坡、厚度等指标易于控制。3.2.2控制好混合料配合比及含水量为提高基层平整度方便摊铺机铺筑及对纵横向裂缝的有效预防,基层的混合料级配一定要严格控制。设计级配与实际级配之间的差异应在可控范围之内。在设计生产配合比时,先要对冷料仓皮带转速与冷料的流量进行了解,测定电机的转速与上料流量之间的关系。根据测出的几组速度-流量关系曲线获得实际需要的皮带转速,生产时就能使拌合料更好的控制在级配范围内,提高
11、冷料之间的配合比精度,有助于设计级配与实际级配相一致,减小偏差。且在做配合比设计时最大粒径适当减少。因为集料粒径越大,混合料越易产生离析,因此适当减少集料最大粒径,严格控制级配有利于摊铺机作业和基层顶面的平整度。另外,混合料施工含水量的控制也十分重要,含水量过小影响结构的粘结力及板体强度,含水量过大碾压成型困难,且易形成路面基层上的波浪和表面有明显的轮迹,致使基层顶面平整度降低,甚至导致结构层收缩开裂。3.3摊铺机械及摊铺作业对平整度裂缝的影响沥青混合料与摊铺机性能及操作水平是影响沥青混凝土路面平整度的直接因素。摊铺机结构参数不稳定,行走装置打滑,摊铺速度不均匀,摊铺不连续,频繁停车,起步猛烈
12、,运料车倒车时撞击摊铺机,倒料时料斗倾卸不均匀,或卸料中制动,熨平板工作不正常,散落在下层的沥青混凝土散料未及时清除,都会造成路面不平整甚至波浪或产生裂缝。(1)根据路面等级,选择性能优良,结构参数稳定,找平装置自动化程度高,与拌和机能力匹配的 摊铺机。(2)保持连续均匀不间断摊铺:有时停机待料、停机用餐,加油等都会出现横向接缝或产生波浪,因为摊铺机每启动一次,自动找平装置都需要在运行38m后才能恢复正常,所以当沥青拌和站的生产能力与摊铺机的摊铺能力相匹配,摊铺机能连续均匀不间断地作业时。速度一般应控制在每分钟26m,保持摊铺速度不变(根据拌和机、运输车辆供料情况,以不停机为原则)。如拌和机稍
13、小,可用储料仓加班生产的沥青混凝土存料保证摊铺机不停机。摊铺机瞬时速度变化,造成铺出的面层粗糙度不均,振捣间隔不均,必然造成平整度下降。所以,摊铺机速度一经选择,应保持均衡,不得经常变换。并尽量做到摊铺过程中不停机。同时应加强管理,对所有的机械加强管理维修,保证连续供料、连续摊铺,利用操作手轮换休息等办法,减少摊铺机的停机次数,提高沥青混凝土路面摊铺的平整度及预防裂缝而且公路沥青路面施工技术规范(JTJ01497)也要求:“摊铺过程中不得随意变换速度或中途停机”,这是提高沥青路面平整度和预防裂缝的一个关键环节。因为摊铺的速度不恒定,会导致摊铺层初始密实度不均匀,从而引起碾压后局部厚度的变化而影
14、响平整度。由于摊铺机摊铺的速度要根据试验路段来确定,既不能太快也不能太慢,摊铺速度过快,易造成摊铺表面的粗颗粒在熨平板下沿摊平方向滑动,使表面粗颗粒后方出现小坑小洞,从而影响平整度和预压密实度,但也不能太慢,否则会影响生产效率。(3)运料车不得冲撞摊铺机和卸料过猛,也不得在卸料中制动而加大摊铺机运行阻力,否则,会引起摊铺机速度变化,会形成“波浪”、“搓板”等现象。要求运料车与摊铺机推动轮轻柔接触,运料车卸料时料斗均匀起升。卸料过程挂空挡,靠摊铺机平稳推进。(4)熨平板振动频率要调整适当,频率过小,预压实度达不到要求,碾压滑移严重;振动频率过大,易引起熨平板共振,特别是铺层较薄时,引起“发白”现
15、象。此外,熨平板要充分预热后才能开始工作,但温度不能过高,以免造成熨平板变形或沥青焦化。摊铺机的起步与熨平板的起振应同步,以保证沥青混凝土料在一开始经小振幅振动,均匀分布,使铺层达到较为均匀的密度。若起步、震动两个动作不同步,会导致面层料局部密度不一致,降低平整度。(5)运料车卸料时或其他原因洒落在地上的散料应及时清理,否则,两侧履带因洒落影响接地标高与横坡不一致时会产生波浪,影响平整度。另外在摊铺作业时,常因运料车操作不熟练而与摊铺机配合不协调,使混合料洒落在摊铺机行车履带前,如不及时清除,会使摊铺机上下左右晃动造成摊铺机上下波动;自动调平系统工作仰角发生变化,影响沥青路面平整度。所以要设专
16、人指挥倒车,运料车要与摊铺机默契配合,卸料时应分二次卸完,不要一次将料倒入摊铺机料斗内,并对洒落在摊铺机履带下的混合料及时清除。3.4碾压工艺对路面平整度的影响。温度太高时碾压容易使沥青混合料产生推移、开裂;碾压行进路线不当,会引起路面不平;碾压速度不均匀、急刹车、突然起动、随意停置、掉头转向等都会引起路面推拥。3.4.1碾压的温度对平整度的影响摊铺好的沥青混合料在何种温度下碾压,直接影响着沥青混凝土路面的平整度和压实度。温度太高容易使沥青混合料产生推移、开裂,温度太低会导致沥青混合料颗粒之间摩擦阻力加大,使沥青混凝土面层压实度不均匀,容易产生局部松散和开裂以及日后渗水导致路面的损坏,严重影响
17、了路面的平整度,所以沥青混凝土路面的碾压温度控制是沥青混凝土路面施工过程中的关键,现场应有专人负责对运输车运输的混合料摊铺前、摊铺后、碾压前、碾压中及碾压终了的温度进行测试,以保证沥青混凝土路面的平整度。3.4.2碾压方式及碾压的速度对平整度的影响碾压沥青混合料采用的组合碾压方式,初压时,首先采用双轮压路机碾压两遍,速度为1.52km/h;复压紧接在初压后进行,应采用重型压路机械压45遍,速度为3.54.5km/h;终压采用轻型压路机碾压两遍,速度为2.53.5km/h;碾压时除按规定的标准外,应注意碾压路线和方向不得突然改变,以免使混合料产生推移而影响平整度。3.5正确使用压路机对平整度的影
18、响路面平整度好坏的关键在摊铺机,但与压路机的碾压有着不可分割的关系,合理的碾压工艺与正确的碾压操作是保证路面平整度的重要手段。使用轮胎压路机时,应注重检查各个轮胎的新旧程度和压力,必须做到新旧一致,压务相同,否则轮胎软硬不一,在碾压过程中形成轮迹,使沥青路面平整度超标。钢轮压路机应装雾状喷水装置以防混合料粘轮,严禁采用人工向压路机的钢轮上洒水,因为洒的水不成雾状也不均匀会造成局部沥青混合温度迅速下降,影响沥青混凝土的平整度。轮胎压路机应有专人负责用1:3的油水混合液喷洒轮胎表面,防止碾压时将沥青混合料粘起形成路面不平整。压路机不工作时应停在冷却后成型的沥青路面或结构物上,否则会形成小坑槽影响平
19、整度。4、施工缝(纵、横)对平整度的影响沥青混凝土路面施工,施工接缝是必然存在的,接缝处常因结合强度不够产生变形、裂纹、松散或出现错台等不平整现象。沥青混凝土路面施工缝处理的好坏对平整度有一定影响,往往连续摊铺路段平整度较好,而接缝处的一个点数据较差。因此,接缝水平是制约平整度的重要因素之一。处理好接缝关键舍得切除接头,用3m直尺检查端部平整度,以摊铺层面直尺脱离点为界限以切割机切除挖除。新铺接缝采用斜向碾压法,适当结合人工找平可以消除接缝的不平整是前后两段路平顺衔接。而施工单位往往为了省料而切缝不到位,引起平整度不佳,横缝应以直线为宜,并且设专人进行处理,以确保接缝处的平整度。4.1纵向热接
20、缝先铺沥青混凝土的一边在压实时预留一定宽度,待后面的摊铺机铺完后一起压实即可。这样,看不到接缝。热接缝的碾压应放在错轮碾压的最后进行,由一台压路机最终完成,不要换机。4.2纵向冷接缝不在同一时段铺筑的纵向缝,及时将缝带位压实,在下次铺筑前把边缘切成垂直面,将后铺的沥青混凝土料与已铺部分重叠510cm,即保证松铺厚度,再用人工将原路面上的沥青混凝土料铲除,最后用钢轮压路机按纵向15cm间隔逐步错轮跨越纵向接缝进行压实。纵向冷接缝在实施时,上下层纵向接缝不得重合,错开量不得小于50cm.4.3横向接缝施工中,尽量保持路面沥青混凝土铺筑连续进行,横向接缝越少越好。对横向接缝应在下次摊铺前,用平整度仪
21、或3m直尺检查端部平整度,将不符合要求的端部用切割机切除,在切割面上涂上乳化沥青,用摊铺机熨平板或用热料将原压实部位进行预热甚至软化,摊铺时保证松铺厚度,必要时用人工刮洒一层细料,然后用钢轮压路机横向碾压,由冷到热,以每次20cm宽度为宜,向新铺方向错移,直至全部在新铺面上为止。改为纵向碾压时,不要在横接缝上垂直碾压,以免引起新旧层错台,并及时测量平整度,如不符合及时处理。5.结束语以上是对沥青混凝土路面平整度及预防裂缝影响因素的分析认为沥青路面预防裂缝及平整度涉及的面很广,影响因素很多,它关系到路基、路面施工全过程,情况复杂,有的是施工工艺不当或机械性能引起,有的是人为操作、安排失误造成的,
22、但只要认真的、科学的对待,做到材料选用优良,设备配置先进合理,施工工艺先进,施工组织严密,全员质量意识增强,各个环节不放松,沥青混凝土路面保持较高平整度及有效防止裂缝的目标是完全可以实现的。参考文献:1交通部公路科学研究所。JTGF402004公路沥青路面施工技术规范s.北京:人民交通出版社,2004.(英文版 ) Two regulations promulgated for implementation is in the party in power for a long time and the rule of law conditions, the implementation of
23、 comprehensive strictly strategic plan, implementation in accordance with the rules and discipline to manage the party, strengthen inner-party supervision of major initiatives. The two regulations supporting each other, the adhere to a positive advocate, focusing on morality is of Party members and
24、Party leading cadres can see, enough to get a high standard; around the party discipline, disciplinary ruler requirements, listed as negative list, focusing on vertical gauge, draw the party organizations and Party members do not touch the bottom line . Here, the main from four square face two party
25、 rules of interpretation: the first part introduces two party Revised regulations the necessity and the revision process; the second part is the interpretation of the two fundamental principles of the revision of laws and regulations in the party; the third part introduces two party regulations modi
26、fied the main changes and needs to grasp several key problems; the fourth part on how to grasp the implementation of the two regulations of the party. and revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Communist Party members and leading cadres ho
27、nest politics several guidelines and column 1 by 2015 to strengthen party laws and regulations focus. Two party regulations revision work lasted a Years, pooling the wisdom of the whole party, ideological consensus, draw historical experience, respect for the wisdom of our predecessors, which reflec
28、ts the unity of inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the partys leadership, to solve the masses of the people reflect a focus on the problem. The new revision of the and , reflects the partys 18 and the eighth session of the third, the spirit o
29、f the fourth plenary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech, reflects the partys eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of in based on revised, the promulgation
30、 and implementation of January 2010, to strengthen the construction of the contingent of leading cadres play an important role. But with the party to manage the party strictly administering the deepening, has not been able to fully meet the actual needs. Content is too complicated, eight prohibition
31、, 52 are not allowed to hard to remember, and also difficult to put into practice; the second is concisely positive advocated by the lack of prohibited provisions excessive, no autonomy requirements; the third is banned terms and discipline law, both with the party discipline, disciplinary regulatio
32、ns repeat and Criminal law and other laws and regulations repeat; the fourth is to clean the theme is not prominent, not for the existing problems, and is narrow, only needle of county-level leading cadres above. is in 1997 based on revision, in December 2003 the promulgation and implementation, to
33、strengthen the construction of the party play very important role. Along with the development of the situation, which many provisions have been unable to fully meet the comprehensive strictly administering the practice needs. One is Ji law, more than half of the provisions and criminal law and other
34、 countries laws and regulations Repetition; two is the political discipline regulations is not prominent, not specific, for violation of the party constitution, damage the authority of Party Constitution of misconduct lack necessary and serious responsibility to pursue; third is the main discipline
35、for the leading cadres, does not cover all Party members. Based on the above situation, need to and the two is likely to be more relevant regulations first amendment. By revising, really put the authority of Party discipline, the seriousness in the party tree and call up the majority of Party member
36、s and cadres of the party constitution of party compasses party consciousness. (II) two party regulations revision process the Central Committee of the Communist Party of China attaches great importance to two regulations revision . Xi Jinping, general books recorded in the Fifth Plenary Session of
37、the eighth session of the Central Commission for Discipline Inspection, on the revised regulations made clear instructions. According to the central deployment, the Central Commission for Discipline Inspection from 2014 under six months begin study two regulations revision. The Standing Committee of
38、 the Central Commission for Discipline Inspection 4 review revised. Comrade Wang Qishan 14 times held a special meeting to study two regulations revision, amendment clarifies the direction, major issues of principle, path and target, respectively held a forum will listen to part of the province (are
39、a) secretary of the Party committee, Secretary of the Discipline Inspection Commission, part of the central ministries and state organs Department The first party committee is mainly responsible for people, views of experts and scholars and grassroots party organizations and Party members. Approved
40、by the Central Committee of the Communist Party of China, on 7 September 2015, the general office of the Central Committee of the Party issued a notice to solicit the provinces (autonomous regions, municipalities) Party, the central ministries and commissions, state ministries and commissions of the
41、 Party (party), the General Political Department of the military, every 3 people organization of Party of two regulations revision opinion. Central Commission for Discipline Inspection of extensive solicitation of opinions, careful study, attracting, formed a revised sent reviewers. In October 8 and
42、 October 12, Central Committee Political Bureau Standing Committee and the Political Bureau of the Central Committee After consideration of the two regulations revised draft. On October 18, the Central Committee of the Communist Party of China formally issued two regulations. Can say, two laws amend
43、ment concentrated the wisdom of the whole party, embodies the party. Second, and revision of the basic principles of two party regulations revision work and implement the partys eighteen, ten eight plenary, the spirit of the Fourth Plenary Session of the Eleventh Central Committee and General Secret
44、ary Xi Jinping important instructions on the revised and , highlighting the ruling party characteristics, serious discipline, the discipline quite in front of the law, based on the current, a long-term, advance as a whole, with Bu Xiuding independent and . Main principle is: first, adhere to the par
45、ty constitution to follow. The constitution about discipline and self-discipline required specific, awaken the party constitution of party compasses party consciousness, maintaining the authority of the constitution. General Secretary Xi Jinping pointed out that no rules, no side round. Party consti
46、tution is the fundamental law, the party must follow the general rules. In early 2015 held the eighth session of the Central Commission for Discipline Inspection Fifth Plenary Session of the 16th Central Committee, Xi Jinping again pointed out that constitution is the party must follow the general r
47、ules, but also the general rules. the revision of the and is Method in adhere to the regulations established for the purpose of combining rule of virtue is to adhere to the party constitution as a fundamental to follow, the constitution authority set up, wake up the party constitution and party rules the sense of discipline, the party constitution about discipline and self-discipline specific requirements. 4 second is to adhere to in accordance with the regulations governing the party and the party. The Party