路基及附属工程施工方案、施工方法
一、路基工程施工方案
（一）路基工程概况
本合同段主线整体式路基，宽24.5米，行车道宽2×2×3.75m，分离式路基宽2*12.25m。
（二）施工队伍安排
本合同段拟配备2个路基工程施工队来完成路基施工，任务划分详见前述“管区任务划分表”。
（三）施工机具配备
采用主要施工机械设备见投标文件技术建议“设备”。
（四）路基施工方案
路基工程施工结合结构物施工进行统筹安排，通道、涵洞施工时应与路基工程配合施工，以便及早大面积展开路基土石方施工。
路基土石方施工采用机械化作业。挖方利用方运距在100米以内的采用推土机施工，运距在100m～700m时采用铲运机施工，运距大于700米的地段采用挖掘机、装载机配合自卸汽车挖运，填方路段按照横断面全宽水平分层逐层填筑、压实。
路基防护和排水工程与路基工程交叉施工，协调安排。挖方边坡开挖一级，及时防护一级。排水工程采用机械配合人工挖沟，人工砌筑施工。
路堑土方开挖采用机械直接开挖，人工辅助整修边坡。机械不能直接开挖的石方采用爆破法开挖。
（五）路基工程进度计划
施工进度计划：自2008年2月1日至2009年5月31日（不含施工准备），共计16个月完成路基工程施工。
（六）土石方调配方案
路基土石方除利用方外，其余均弃于设计指定的弃土场。
二、路基工程施工方法
（一）路堑挖方施工
1、路堑施工方法
（1）土方开挖施工要点：土方直接用挖掘机开挖，自卸汽车运输。
① 路基开挖前作好截水沟，施工期间修建临时排水设施，力争作到永临结合。
② 土方开挖均应自上而下进行，不得乱挖超挖，严禁用爆破法施工和掏洞取土。边坡配以人工分层修刮平整。
③ 开挖过程中如遇土质变化需修改施工方案及边坡坡度时，应及时报批。
④ 挖方路基施工标高，应考虑因压实而产生的下沉量，其值由试验确定。开挖至路基施工标高后必须立即进行排水边沟的施工。
⑤ 开挖的土方如符合路基填料标准，将土方运至填方地段作为路基填料用，否则作为弃土运至弃土场。
⑥ 深挖路堑施工时，边坡严格按图纸坡度施工，并充分作好排水设施。开挖后及时施工边坡防护。
⑦ 当因气候条件使挖出的材料不能用于路基填筑和压实时，应停止开挖，直到气候条件转好。
（2）石方开挖施工要点：采用潜孔钻机配以凿岩机钻眼，松动控制爆破和边坡成型光面爆破。
① 石方开挖根据岩石类别、风化程度和节理发育程度，确定开挖方法。对于软石和强风化岩石能用机械开挖的采用机械开挖，不能用机械直接开挖的石方，采用爆破法开挖。
② 石方爆破采用预裂、光面、控制爆破技术，有效控制断面，不允许过量爆破，否则自费清理设计断面以外由于爆破所松动的全部材料，弥补环境损害，直至监理工程师满意为止。
③ 爆破作业应防止损坏路床，路床应采用相同强度的材料整平，并用冲击振动压路机碾压，将凸起处压碎，将凹陷处回填压实，提高路床的均匀性。
④ 施工时最大限度的利用开挖的石方，除用于路堤填方外，质量符合要求的石料加工成片石、块石、碎石，用于砌石和路面底基层及结构物混凝土集料，不允许随意弃方。
⑤ 石方路堑的路床顶面标高，要符合图纸要求，高出部分用人工凿平，超挖部分按监理工程师批准的材料回填并碾压密实稳固。
路基挖方施工工艺详见“第十二章 主要分项工程施工工艺框图”。
2、施工控制及检测
路堑开挖前做好排水工程，以防雨季洪水对边坡冲刷，施工期间始终保持排水系统畅通。
路堑开挖在接近设计标高时配以小型机械作业，以防超挖，开挖自上而下进行，不准掏底开挖。
需设防护的边坡，要按设计要求及时支护，不得长期暴露，以免造成坡面坍塌。
路堑开挖除对边坡坡率以及路肩标高、宽度进行控制外，还要对基床填料及压实度进行严格控制。
对于不属于施工引起的滑坍，应按监理工程师指定的边界或坡度进行挖除后用于路堤填筑或其他处理。
3、石方爆破施工
在石方爆破作业前，要根据地形地质，开挖断面及施工机械配备等情况，编制实施性爆破施工技术设计方案，报请监理工程师批准，并严格按照监理工程师的指令执行。
本合同段拟采用潜孔钻机布孔进行分层、分段、光面、小药量控制爆破技术施工。路基石方在施工过程中对开挖高度小于5米的边坡采用风动凿岩机钻孔，浅孔爆破；对于开挖高度大于5米的采用潜孔钻机钻孔，深孔控制爆破；10米以上者分台阶爆破。爆破采用电雷管毫秒微差起爆网路联接，两侧边坡采用预裂爆破，间隔装药、底部加强装药技术，整个爆破采用孔内分排延时，孔外组间延时，同组即发技术，从而保证爆破后边坡稳定及附近通讯、电力线路、居民的安全。爆破后的块体要适中，大块率控制在7%以内，能满足机械装运作业，能适合路基填料要求。
为了进一步提高机械设备一条龙作业效率，钻爆配置潜孔钻机、7～9m3内燃空压机，装运配置推土机、挖掘机、自卸汽车，钻爆装运实行一条龙作业。
双边坡路堑和不能横向开挖的单边坡路堑，采取分梯段纵向开挖。单边坡路堑先挖浅地段，再挖深地段，以增加开挖工作面。
本合同段石方爆破采用深孔控制爆破和光面爆破相结合的施工方案。
根据石方开挖施工经验，计划采用潜孔钻机布孔进行深孔控制爆破技术施工。深孔控制爆破是把一柱形药包分散在岩石体内进行爆破，可以做到“二控制”：控制飞石和控制爆破振动波，最大限度地消除爆破振动对路堑边坡稳定及山体滑坡地段的影响，起爆方式采用毫秒微差起爆技术，利用微差挤压爆破可以开辟的自由面，压缩波与反射波相互迭加，石块粒径能够控制，破碎效果好，便于装运及做填料。
在深孔控制爆破施工中，按照设计要求首先对场地布局分段平整，规范布孔操作和孔位选择，严格控制装药量，注意装药与填塞质量及网路连接和起爆等工序，选择施工间歇作为安全放炮时间，避免作业干扰、提高工作效率。
光面爆破是主体药包爆破之后，利用布设在设计开挖轮廓线上的光爆炮孔，准确地将预留的光爆层从保留岩体上切下来，形成平整的开挖坡面。
（二）路基填筑施工
1、工艺试验
路基填筑施工前，对各种类型的路基填筑选择地质条件、断面形式具有代表性的地段（长度不小于100米的全幅路基）做工艺试验路段，从中选出路基施工的最佳方案、工艺参数和检测方法来指导施工。试验时作好记录，对压实设备的类型、最佳组合方式、碾压遍数及碾压速度、工序、每层材料的松铺厚度等写出试验报告报工程师批准，进而严格施工工艺，明确检测方法，确保施工质量。施工中若现场填料发生变化，应及时进行试验，并报监理工程师审查和批准。
2、路基填筑施工要点
方案要点：土石方运距在100米以内采用推土机施工；当土石方运距在100～700米时，采用铲运机施工；当土石方运距在700米以上采用挖掘机、装载机配自卸汽车机械化组合施工方式。
本合同段路基施工全部采用机械化作业，压实采用推土机、平地机摊平预压，填土路基用激振力大于40吨的压路机碾压，填石路基先用羊足碾碾压，再用激振力大于50吨的压路机碾压。对特殊地段及特殊部位，采用冲击式压路机碾压。涵洞通道两侧、桥台背后等狭窄地点，用小型机械振动夯实。
（1）基底处理
一般路堤段填筑范围内，对原地面行表面清理，按设计及规范要求的深度将农作物根系、树根全部清除。场地清理完后，填前对基底进行全面碾压密实至规定的压实度。
当原地面横坡陡于1∶5时，路基基底开挖宽2m，内倾坡度为4%的台阶。
零填挖和填土高度＜80cm（不包括路面厚度）路段，按招标文件要求进行处理。
软土路段及浸水路基，先清除淤泥，按设计进行加固处理。
（2）土方填筑
填方路基按路面设计线平行分层填筑，每层的填筑面要作成不小于3%的横坡，以利排水。
采取分层平行摊铺并压实，每3层进行一次精确放样，并用平地机找平整形，使填筑面满足设计纵、横坡要求。每层施工打格上土，标杆控制，每层松铺厚度由现场工艺试验确定，应控制每层最大松铺厚度不得大于30cm，最小压实厚度不得小于10cm。
在填筑过程中根据选定的最佳含水量对填土或洒水或翻晒晾干，将含水量控制在最佳含水量的±2%范围内。每层填筑前必须湿润工作面。每层填料每侧宽于填层设计宽度30cm，碾压的轮迹要重叠20～30cm。
填土路基分段作业时，先施工路段端部必须留不陡于1:5的坡面，坡面必须整平压实，以便施工机械上下及下段路基施工时开台阶。
（三）石方填筑
路堤填筑所用石料强度、粒径及摊铺层厚满足设计及招标文件技术规范要求。
填石路堤采用逐层水平填筑，采取填筑顶备料向前推摊整平的方法组织施工，不宜采用成堆备料平铺方法。采用大功率推土机和重型振动压路机分层铺筑、压实。
逐层填筑时安排好运输线路，专人指挥，按照水平分层填筑，先低后高，先两侧后中央卸料，并用大型推土机摊平，个别不平处配合人工用细石填，石屑找平。其它要求按设计、招标文件和现行施工规范严格执行。
（4）路基检测
路基每碾压完毕一层及时检测一层，路基填土压实度检测可采用核子密度仪、环刀法或灌砂法，填土强度检测可采用K30承载板、CBR值强度检测、贝克曼梁法。通过不同的检测方法检测，找出不同方法之间的相关性，确保检测数据可靠，达到控制密实度、力学性能质量的要求。高填方地段，可通过室内试验，填料在不同压实系数的重塑状态下，进行剪切、压缩试验，计算出填料层的最终累计变形量，同时在基底埋设沉降杯、柔性沉降传感器等测试原件对路基沉降进行长期观测。
（5）路基整修
①按设计图纸要求，恢复各项标桩，检查路基中线位置、宽度、纵坡、横坡、边坡及相应的标高等。根据检查结果编制整修计划报监理工程师批准后方可施工。
②土质路基用人工或机械自上而下修整。每填2m高时，即修整填方边坡，深路堑边坡整修按设计要求的坡度刷坡，挖3m深时，即修整边坡。
③石质边坡要准确地修整，使之符合设计要求，坡面上松动的或突出的石块，要及时清除。
④整修需加固的坡面时，预留加固位置；当填土不足或边坡受雨水冲刷时，将原边坡挖成台阶，分层填补夯实，若填补的厚度很小（10-20cm），而又是非边坡加固地段时，以种植土来填补。
⑤路基表面达到设计标高后采用平地机或推土机刮平，铲下的土不足以填补凹陷时，采用与路基表面相同的土填平夯实。
⑥边沟的整修应挂线进行，对各种水沟的纵坡均采用仪器检测，整修到符合设计及规范要求为止。
⑦填土路基两侧超填的宽度要切除。
⑧路基整修完毕后，清除路基范围的废弃土料。
路基填筑施工工艺详见“第十二章 主要分项工程施工工艺框图”。
3、高填方路基填筑施工
高填方路堤的填筑除应满足一般路堤填筑的要求外，还应注意以下几点：
（1）高填方路堤严格按设计边坡分级填筑，不得任意改变设计边坡。
（2）高填方路堤基底应按设计及规范要求进行场地清理并压实。
（3）高填方路堤分层压实松铺厚度与一般路段填方相同，应根据填筑材料类别和压实机具性能通过试验确定。如填料来源不同，其性能相差较大时，应分层填筑，不应分段或纵向分幅填筑。
（4）高填方路堤受水浸淹的部分采用水稳性好或渗水性好的填料，边坡比要符合图纸要求。
（5）半挖半填的一侧基底为斜坡时，按规定挖好横向台阶，并在填方路堤完成后，对设计边坡外的松散弃土进行清理。
（6）高填方路堤必须进行沉降和位移观测，观测方法按技术规范有关规定办理或经监理工程师批准的其它方法。
Construction Scheme and Method of Subgrade and its attachment Project
I. Construction plan of subgrade engineering
(I) General situation of subgrade engineering
The main line of this contract indludes: integral subgrade, 24.5m wide, with driveway width 2×2×3.75m, and secrete subgrade, 2*12.25m wide.
(II) Arrangement of construction teams
We pre-arrange two construction groups of subgrade engineering to finish the subdgrade construction of this contract. You can find the detail division of task in “List of Task Division in Management Areas”.
(III) Arrangement of construction machines
The main construction machines are suggested “equipment” in technique disposal of procurement document.
(IV) Construction plan for subdgrade
Construction of subgrade is carried out overall arrangement by combining structure. The construction of tunnel and culvert should wor in with each other to start subgrade’s earthwork construction early.
Subgrade’s earthwork construction is carried out by machine. If the transport distance from dig place to fill place is less than 100m, we main use bulldozer. 100-700m, use Load-Haul-Dump. Over 700m, use grab, loader and dump truck. Fill place fill, press it gradually according to transect.
Protection and drainage project of sumgrade is carried out crossly. When dig one-step, we should protect it in time. We use men and machine to finish the drainage project, men build the defense.
High Cutting earthwork mainly use machine to dig directly, man will refit the slope. The stone that cannot be dug directly can use blasting operation.
(V) Progress plan of subgrade engineering
Construction plan: finish this construction in 16 months, from Feb 1, 2008 to May 31, 2009(except preparation time).
(VI) Arrangements of earthwork and stonework
Except the earthwork that used in Subgrade, the others will be put into the appointed waste bank place.
II. Construction ways of subgrade engineering
(I) Construction of cutting excavation
1. Construction ways of cutting excavation
（1）Elements of earthwork excavation: Use grabs to dig earthwork directly, then transport by dump truck
① In order to finish the engineering successfully, we need to prepare the intercepting ditch before digging the subgrade. During the construction, we must build temporary drainage establishment.
② The excavation of earthwork should be from top to bottom, and should not dig randomly and excessively. Forbid the use of blasting operation and hollow out earth. The side slope flat is modified by labor assisted.
③ During the process of digging, if there is a need to change construction plan and gradient of side slope because of the change of soil, you should report to related people to get modification plan.
④ When the digging side have elevation, they should considering sunken which caused by press. Its value decided by test. When dig to the elevation, they should make drainage gutter immediately.
⑤ If the digging earth fit the fill standard, the earth will be transported as fill to the fill place. Otherwise, they will be transported to wasted land.
⑥ When digging high cutting deeply, side slope’s gradient should be the same with design, and we should be prepare drainage instrument well.
⑦ When earthwork that was dug out does not fit for fill because of weather condition, they should stop dig, and wait the weather gets better.
（2）Elements of stonework excavation: Use down-hole drill assisted with hammer drill drilling. Control blasting loosely and side slope molding smoothing wall blasting.
① Stonework excavation is based on stone type, weathering degree and joint develop degree. The soft and strong weathering stone will be dig by machine if they can. If not we can use blasting operation.
② Stone blasting mainly use Pre-splitting, finish and control blasting to control section effetely. Forbid blasting excessively. Otherwise, they should in charge with clean all loose except section, and make up the environment damage until Supervision Engineer satisfied.
③ Blasting should prevent damage road. The road should be filling with same material, use vibratory roller to press. So that, the road will be flat and its equality will improve.
④ We should make great use of the dug earth. Except filling, the stone which accord with requirement can be made into block stone, rushed stone and rubble stone that can be used as build stone, layer ground and concrete material. Forbid to abandon them.
⑤ The top elevation value of stone high cutting’s roadbed should be accord with design. The exceeding part should be cut manually, while the sunken part should be filled according to the Supervision Engineer’s requirement.
Precise information about the construction craft of subgrade excavation is in “Chapter 12 Chart of Various Sub-Engineering Construction Processes”
2. Construction control and inspection
Before dig high cutting, we should prepare well for drainage. In case flood wash the side slope in rainy season. During the construction, we should make sure the drainage instrument free all the time.
When cutting high nearly reaches to the design elevation, we should use miniature machine to prevent dig excessively. Digging should be carried out from top to bottom, forbid to dig from bottom.
If need to protect side slope, we should protect according to design. In case of crush, they should not expose for a long time.
When dig high cutting, except the control of side slope angle and shoulder (road)’s elevation, width. We also should control roadbed’s filling and press degree.
While for the crush that aroused by other reason, they should be cut according to the Supervision Engineer appointed side or gradient, and the things that dig out can be used as fill or others.
3. Stonework blasting construction
Before stonework blasting, we should make out an enforceable blasting construction plan. According to landform geology, section and construction machine and so on. This plan should get the approval of Supervision Engineer, and be carried out strictly according to the Supervision Engineer’s instruction.
We use in-the-hole drill rigs to stratify, separate, smooth, blasting by small dose techniques. During rock roadbed construction, the excavation slope is less than 5 m, using pneumatic rock drill boreholes, shallow hole blasting. the excavation slope is more than 5 m, using in-the-hole drilling rig drilling, deep hole controlled blasting. More than 10 m, using the bench blasting. Electric detonators use millisecond blasting network connection. Both sides slope using presplit blasting, interval charge, strengthen the bottom charge technology. The entire blasting use hole points by blasting delay, the hole outside the group delay, the same group that is the technology. So we can stability of side slope and near telecommunications, electric power lines, the safety of residents after blasting. After the blasting, the block must be moderate, the bulk rate must be within 7%, can meet the shipment operating machinery, can requirement for roadbed filler.
In order to improve the efficiency of machinery, drilling with blasting in-the-hole drilling rig, 7 - 9 m3 internal combustion air compressor, transport-using bulldozers, excavators, dump truck. Drilling, blasting and transport at the same time.
Bilateral high cutting and unilateralism high cutting cannot be dug, excavating gradually. Unilateralism slope first dig shallow lots, then deep one to increase the excavation scale.
The stonework blasting of this contract uses construction program that combine blasting deep hole and smooth blasting.
According to experience of stonework excavation, we plan to adopt a in-the-hole drill to have deep hole controlled blasting technology. Deep hole controlled blasting puts pole drug distributed in rock for blasting, which can have "two controls”. Control fly-stone and blasting vibration wave, which furthest eliminates the influence to the stability of cutting excavation slope and landslide section caused by blasting vibration. Detonation methods used millisecond technology, using millisecond blasting can open up the free surface, the compression wave and reflect wave mutual superposition, the particle size of stonework can control , broken effect is very well, and facilitate transport to filling place.
During the construction of deep-hole controlled blasting, firstly we need to make subparagraph flat, standardized operation and choice hole’s place according to the design requirements. Control the quantity of drug strictly. Pay attention to drug install, packing quality, network connect and detonation processes. Choose construction intermission as security blasters time. Avoid interference operations and enhance efficiency.
Smoothing wall blasting after the main blasting, using excavating use emplaced in the design of the contour line-blasting holes, and accurately will be reserved for the optical layer from the reservation stonework blasting on cutting down a slope formed excavation.
(II) Subgrade filling construction
1. Process Test
Before filling construction of the subgrade, we should have a whole test of various types construction subgrade’s choose geological conditions, the form of a representative section (the length of whole is less than 100 m). Then select the best plan for roadbed construction, process parameters and inspection methods to guide construction. When have the test, we should make a records, such as the type of compaction equipment, the best combination and rolled times and speed, processes, the material thickness of each step. Then submit them to engineers for confirm. So we can strict construction technology, make detection methods clean and to ensure construction quality. If fill changed, we need to test it immediately, and submit to supervision engineer review and approval.
参考资料：http://www.jgzj.net/bbs/thread-214780-1-1.html