有绿化带老路改造为一块板新路时绿化带处理技术

【作者】 王淑贞；

【导师】 商庆森；

【作者基本信息】 山东大学 ， 固体力学， 2005， 硕士

【摘要】 目前,随着我国经济的发展,各城市的发展建设进入了一个前所未有的快速发展的时期,城市道路的改造也遇到了新的机遇和挑战。在城市道路改造过程中经常遇到将原有老路绿化带拆除,进行处理后与老路面一起进行路面结构层补强,以增加道路有效行车宽度的改造方法。本文结合205国道滨州北出口路面改建工程实践,通过现场施工与室内试验,对老路绿化带的处理技术以及提高补强路面结构层整体强度,防止路面因不均匀沉降而形成纵向的裂缝,最终导致路面结构性破坏的方法进行深入的探讨和研究,以求找到既经济又方便适用的有效处理办法。 在205国道滨州北出口路面改建工程的施工中主要采用了以下方法:(1)老路绿化带-20CM至-80CM范围的处理结合当地自然地理条件及缺乏无机结合料稳定材料的情况,从技术、经济角度综合评价,选定石灰稳定土方案;同时提出了施工过程中控制新路基弯沉值不大于老路基弯沉值,绿化带顶面弯沉值不大于老路面弯沉值的检测标准;(2)绿化带0至-20CM处向老路两侧开宽各25CM的台阶,并用抗拉强度和抗压强度都明显高于石灰稳定类的二灰稳定碎石处理,在狭长的绿化带顶部形成简支板结构;同时增设一层道路专用加筋土工布,并对土工布边沿加以固定,使作用在绿化带上部的应力进一步得到分散;(3)路面结构层因半幅施工形成纵向接缝,在两层沥青砼之间,在纵向接缝处加铺一层浸透沥青的土工布,浸透沥青的土工布夹层既可有效减缓反射裂缝,又可防止雨水沿裂缝渗入基层而造成基层的破坏;(4)上面层采用SMA-13结构厚4CM,SMA具有优良的抗车辙性能和抗滑性能,能有效的提高路面耐久性,增强路面结构整体强度。纤维的加入能明显提高沥青砼的抗拉和抗剪性能,回弹模量也有明显提高。 本文还从改进施工工艺方面进行研究与探讨,提出了各道工序施工技术要点以及保证施工质量的措施。在二灰碎石基层施工时:(1)将稳定土拌和机料斗挡板加高一米,防止了各料斗间材料的互相污染,保证了集料配比准确;(2)在料斗各下料口安装了相应筛孔的振动筛,防止了过更多还原

【Abstract】 With the economic development in China, while the city construction develops so rapidly, the highway reconstruction is meeting new opportunities as well as new challenges. During the process of reconstruction of highways there exists such a method that the former seeded strip is cleaned and then is reinforced together with the new base course so as to widen the highway. With the reconstruction practice of the northern part of 205 State Highway within Binzhou city, the thesis introduces an economical and practical method of dealing with the former seeded strip as well as promoting the integral intensity of reinforced base course, which effectively avoids the longitudinal cracks and the structural destruction of the pavement due to the differential settlement.During the process of reconstruction of the northern part of 205 State Highway within Binzhou city, the following precedures have been adopted as: 1) between 20cm and 80cm beneath the former seeded strip, lime-soil stabilization has been selected due to the local geographical features and the shortage of inorganic matrix;meanwhile the Benkelman beams value of the new roadbed is controlled less than that of the former roadbed, and the benkelman beams value of the top surface of the seeded strip is controlled less than that of the former road surface;2) there forms a simple support top, made of the mixture of lime and pulverized coal and crushed stones, on the steps cut from both sides of U-groove which lies 20cm beneath the surface of seeded strip;meanwhile a piece of typical highway steeled geotextile is used to reduce the stress functioning on the top part of former seeded strip;3) a piece of asphalted geotextile covers the longitudinal joint caused by half-pavement construction to effectively reduce the backscattering cracks and to avoid the destruction caused by the rain water;4) SMA-13 structured asphalt concrete is adopted when the top layer is constructed, for SMA has good property against tracking and slippiness, so as to keep the pavement durable and its structural intensity stronger;and the modulus of resilience is greatly improved by adding the fabric in asphaltconcrete which has a property against tensile-shear.Additionally this thesis puts forward some key steps of construction process and some measures of guaranteeing the construction quality. During the process of constructing macadam pavement with the mixture of lime and pulverized coal, 1) the accuracy of aggregate proportion has been guaranteed by heightening 1 meter the bunker baffle of stabilized soil-mixing machine to avoid material being polluted each other;2) the quality of mixed material has been guaranteed by stalling a vibrating screen with proper mesh size at each laying-off exit of the bunker to avoid the oversize aggregate and lime clusters entering the mixing cabinet;3) the friable state of pavement surface has been avoided by positing professional staff to deal with those rubble aggregate on the edge of paving surface before compaction, to get rid of those aggregate clusters and change the even mixing materials after roller compaction once, and to water the paving surface during the process of compaction;4) the pavement planeness has been guaranteed by using paver with stronger jolt ramming power during the process of paving as well as positing professional staff to keep the planeness through levelling and compacting.The northern part of 205 State Highway within Binzhou city has been in good condition, without any longitudinal cracks on the top pavement above the former seeded strip and on the longitudinal joint parts, since it was reconstructed one year ago, although there are just a few lateral cracks inavoidably caused by the shrinked foundation course. The successful reconstruction of the northern part of 205 State Highway within Binzhou city has practical and immediate significance in both guaranteeing its good quality and cutting its cost.更多还原