第一节 公路横断面的组成

第一节 公路横断面的组成 公路中线的法线方向剖面图称为公路横断面图，简称横断面，它是由横断面设计线与横断面地面线所围成的图形。在横断面上的内容包括:行车道、中间带、路肩、边坡、边沟、截水沟、护坡道以及专门设计的取土坑、弃土堆、环境保护等设施，各部分的位置、名称如图1-4-1所示。 横断面设计是路线设计的重要组成部分，它和纵断面设计、平面设计相互影响，所以在设计中应对平、纵、横三个方面结合起来综合考虑，反复比较和调整后，才能达到各元素之间的协调一致，做到组成合理、用地节省、经济和有利于环境保护。 横断面设计的主要内容是:确定横断面的形式，各组成部分的位置和尺寸以及路基土石方的计算和调配。路拱、路面结构和厚度、路基的强度和稳定性以及超高、加宽、平面视距等在本教材的有关章节中介绍。 一、路基标准横断面 路基标准横断面是交通部根据设计交通量、交通组成、设计车速、通行能力和满足交通安全的要求，按公路等级、断面的类型、路线所处地形规定的路基横断面各组成部分横向尺寸的行业标准。各级公路的路基标准横断面如图1-4-2所示。 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through 1(横断面分类 。 高速公路和一级公路的路基横断面分为整体式和分离式两类。上下行的公路的横断面由一个路基形成称为整体式;由两个路基分别独立形成为分离式，整体式横断面上包括行车道、中间带、路肩、紧急停车带、爬坡车道、变速车道等;分离式的断面没有个中间带，其他部分和整体式断面相同。 二、三、四级公路采用整体式断面，不设中间带，它的组成包括行车道、路肩、错车道等，如图1-4-l所示。 2(路基宽度 路基宽度是指在一个横断面上两路肩外缘之间的宽度，一般是指行车道与路肩宽度之和，当没有中间带、紧急停车带、爬坡车道、变速车道、错车道时，应包括在路基宽度内，《公路工程技术标准》规定的各级公路的路基宽度如1-4-1。 一般情况下应采用表1-4-1中的一般值，有条件时还可适当增加硬路肩和路基宽度，以利交通组织和日后交通量增加时拓宽行车道。只有在受地形或特困和其他特殊情况限制时，在局部路段才能使用变化值，且不宜太长，以免影响全路的使用质量。四级公路一般采用3.5m的行车道和6.5m的路基;当交通量较大时，可采用6.0m的行车道和7.0m的路基;当交通量很小或工程特别艰巨的路段，可采用4.5m的路基和3.5m的单车道，但必须设置错车道。 3(行车道 (1)行车道的功能 行车道为车辆行驶提供通行条件，行车道的宽度和路面状况影响车辆行驶的安全性、舒适性和公路的通行能力，行车道过窄会使不同车道之间的横向间距不足，车辆的横向干扰增加，平均速度和通行能力下降: (2)车道数 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through 公路的车道数主要根据该路的预测交通量来确定，行车道的基本数目应在一个较大的路线长度内保持不变，而且当车道数目需要增加或减少时(一次应不多于一条车道，各级公路的车道数见表1-4-1。 (3)行车道宽度 一条车道的宽度必须能满足设计车辆在有一定横向偏移的情况下运行，并能为相邻车道 上的车流提供余宽，所以汽车所需车道的宽度受车速、交通量、驾驶员的驾驶能力、会车等影响，各级公路一条车道宽度的确定见表1-4-2。 4(变速车道 当车辆需要加速合流或减速分流时，应根据公路的等级、使用性质等增加一段使车辆速度过渡的车道，使变速车辆不致因速度的变化而影响其他车辆的正常行驶。在高速公路和一级公路的互通式立体交叉、服务区等与主线连接处(设有变速车道，其宽度一般为3.5m，长度与速度变化范围、车辆特性等因素有关(可经计算确定，一般情况下可采用《公路路线设计》规定的数值。 中间带由路线双向的两条左侧路缘带和中央分隔带组成。中央分隔带是分隔高速公路或一级公路上对向行车道的地带。 (1)中间带的功能 ?分离不同方向的交通流，减少车辆的对向干扰，以防止无序的交叉运行和转弯运行。 ?在不妨碍公路限界的前提下，作为设置公路标牌的场地。 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through ?在交叉路口为左转车辆提供避让区域。 ?提供绿化带，以遮挡对向车灯的眩光。 ?引导驾驶员的视线，同时为失控车辆提供救险区域。 ?埋设管线等设施。 (2)中间带的宽度 中间带的作用明显，但投资、占地多。一般均采用窄分隔带高出行车道表面的中央分隔 带，称为凸形;也有宽度大于4.5m的凹形，表面采用植草、栽灌木或铺面。 中间带可不等宽，也不一定等高，应与地形、景观等配合。不等宽的中间带应逐步过渡，避免突变。中央分隔带每隔2km设置一处开口，供紧急特殊情况使用。中间带宽度见表1-4-4 所示，正常情况下采用一般值，当遇特殊情况时可以采用低限值。 7(路肩 路肩位于行车道外缘至路基边缘之间，是具有一定宽度的带状结构物，高速公路和一级公路的路肩包括硬路肩和土路肩两部分;二、三、四级公路的路肩一般只设土路肩。路肩的主要作用是保护行车道，供行人、自行车通行和临时停放车辆。《公路工程技术标准》规定的各级公路路肩宽 度如表1-4-5 高速公路采用分离式断面时，行车道左侧也应设硬路肩(其宽度为:计算行车速度120km/h时采用1.25m;计算行车速度100km/h时采用100m;计算行车速度小于或等于80km/h时采用0.75m。 高速公路和一级公路应在路肩宽度内设右侧路线带(其宽度一般为0.5m。 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through 四级公路路肩宽度，当采用单车道时，一般为1.5m，其余情况下为0.5m。 8(路缘带 路缘带既可以是硬路肩的一部分，又可以是中间带的一部分，主要取决于它的位置，如图1-4-2。在中间带范围内的路缘带是中间带的组成部分;在路肩范围内的路缘带属路肩的组成部分，它的主要功能是诱导驾驶员视线和提供部分侧向余宽。当汽车越出行车道时，能加强行车安全。 9(应急停车带 应急停车带是车辆发生故障时紧急停车的区域。 应急停车带的宽度包括硬路肩在内为3.5m，有效长度不小于30m、此外在应急停车带的两端还需设置一个斜线的缓和过渡段，长度为20m(对低等级公路可为l0m)。 二、路基典型横断面 在公路设计中，我们把起伏不平的地形变成了可供汽车行驶的公路，因此原地面低于公路的设计线，就需要填筑不足部分;反之，就需要挖去多余部分;若上述两种情况同时出现在一个断面内，就形成既填又挖。我们把高于原地面的填方路基称为路堤，低于原地面的挖方路基称为路堑，在一个断面内，部分要填，另一部分要挖的路基称为半填半挖路基，如图1-4-4。 以上介绍的路基横断面的三种基本形式，由于自然地形、地质条件的多样性，由此可派生出一系列类似的断面形式，它们在公路设计中经常被采用，故称为典型横断面。了解典型横断面的特点，对于结合地形正确地设计路基横断面是十分必要的。 1( 路堤 常用的各种路堤形式如图1-4-5所示。 (1)一般路堤:填土高度大于1m小于20m的路堤。 (2)矮路堤:填土高度小于lm，为排水常需设置边沟。 (3)沿河路堤:路堤浸水部分的路堤边坡采用1:2，并视水流冲刷情况采用。 (4)陡坡护脚路堤:当路堤的坡脚伸出较远且不稳定或坡脚占用耕地较多时，用护脚取代坡脚的路堤。 (5)利用挖渠土填筑路基:这是农田水利建设与公路建设相结合的形式，但需要考虑渠道的水流是否影响公路的正常使用，以及路基在渠道设计水位的影响下强度、稳定性是否满足要求。 2( 路堑 常用的路堑形式如图1-4-6所示。 (1)一般路堑:路堑必须设置边沟，以排除路面积水;为拦截山坡上方的地面水流向路基(在坡顶外至少5m处设置截水沟。路堑挖出的废弃土石方，置于地形下侧的路堑坡顶以外至少3m，形成弃土堆。详细设计参见本教材《路基路面》部分。 (2)台口式路堑:山体的自然坡面为路堑的下边坡，适用于地质状况良好的地段。 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through (3)半山洞:半山洞适用于整体坚硬的岩石层上，为节省工程量采用的—种形式，应用时注意公 路的安全和建筑限界的要求。 3(半填半挖路基 常用的半填半挖路基如1-4-7所示。 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through (1)一般半填半挖路基:半填半挖路基是比较经济的断面形式，注意当原地面横坡大于1:5时，将原地面挖成台阶，以保证填土的稳定。 (2)护肩路基:用于填土高度不大，但坡脚太远不易填筑时的情况(护肩高度一般不超过3m。 (3)砌石路基:用于地面横坡太陡，坡脚落空，不能填筑时。 (4)挡土墙路基:挡土墙是不依靠路基独立稳定的结构物，它也能支挡填方，稳定路基。 (5)矮墙路基:用于挖方边坡土质松散，易产生碎落的情况。 各种典型路基横断面要结合实际地形选用，且应以路基稳定、行车安全、工程量小和经济适用为前提。 三、路基的附属设施 为了保证路基稳定和行车安全，根据实际需要设置取土坑、弃土堆、护坡道、碎落台、堆料坪等路基附属设施，这些都应视为路基主体工程不可缺少的部分。 1(取土坑与弃土堆 公路土石方数量在调配过程中或在公路养护中，不可避免地会在公路沿线附近借土或弃土。在公路沿线挖取土方填筑路基或作为养护材料所留下的整齐土坑，称为取土坑。将开挖路基所废弃的土，按一定的规则形状堆放于公路沿线一定距离内称为弃土堆。无论借土或取土，首先要选择合理的地点。一般应从土质、数量、占地及运输等方面考虑选点;其次要结合农田水利，改地造田，少占或不占良田，维护自然生态平衡合理选点，从而做到“借之有利，弃之无害”。 10m以外，并不得长期积水危害路基或构造物的稳定。 开挖路基的废方，应妥善处理，充分利用;如用于公路、农田水利、基建等，做到变废为宝，弃而不乱，对无法加以利用的弃土，应防止乱弃而造成水土流失，危害路基及农田水利，淤塞河道。 废方一般选择在沿线附近低洼荒地或路堑下坡一侧堆放。沿河路基的废石方，条件允许时(可以部分占用河道，但不能造成河道上游雍水，危及路基及附近农田。如需在路堑上侧弃土，要求堆弃平整，顶面具有适当横坡，并设置平台三角土埂及排水沟渠，如图1-4-9所示。积砂或积雪地段的弃土堆，为有利防砂防雪，一般设在迎风一侧。路堑深度大于1.5m时(弃土堆距坡顶至少20m。浅而开阔的路堑两旁不得设弃土堆。 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through 2(护坡道与碎落台 当路堤较高时，为保证边坡稳定，在取土坑与坡脚之间或边坡坡面上，沿纵向保留或筑成有一定宽度的平台称为护坡道。其目的是加宽边坡横距，减缓边坡平均坡度，护坡道愈宽，愈有利于边坡稳定，但工程量随之增加，根据实际情况，宽度至少为1.0m，并随填土高度增加而增大。一般情况下，护坡道宽度d为:h<3.0m，d=1.0m;h,3~6m，d=2m;h,6~12m，d,2~4m。 碎落台通常设置在路堑边坡坡脚与边沟外侧边缘之间，有时也设在边坡中部，如图1-4-10所示，其作用是防止零星土石碎落物落入边沟，碎落台宽度一般为1.0~1.5m。兼顾护坡道作用，又适当放宽。对风化严重的岩石边坡或不良土质边坡，一般为1.0~1.5m，其顶部宽度大于0.5m，墙高1~2m。 3(堆料坪 为避免在路肩上堆放路面养护用料，在用地条件许可时，可在路肩外绿或边沟外缘设置堆料坪，—般每隔50~100m设置一个，其长度为5~8m(宽度为2m左右，如图1-4-11所示。 supplies and get to use, the registration of company assets, record maintenance, maintenance of effective management; 2.6 cost management: preparation of the annual administrative budget, control administrative costs, determine the scope of cost-sharing, sharing the office expenses by month; 2.7 information management: responsible for documents, materials, information and publicity, communication links, and ensure promptly, ranking officers reporting; responsible for the collation and analysis of information, provide the basis for corporate decisions; corporate culture construction, planning, editing, internal publications; 2.8 vehicle management: responsible for the management, repairs and maintenance of vehicles; 2.9 legal disputes: the company responsible for the handling of disputes; 2.10 other: maintaining normal working order, and security. General Manager General Manager job description 1, 1.1 develop strategies and plans: according to company strategic planning, establish the annual management plan, reported to the Board of Directors for approval; 1.2 decomposition measures: according to the Board of Directors issued the annual management plan, annual index of decomposition, through the Organization of coordination mandate in charge of the Department Organization and implementation, ensuring comprehensive implementation of annual indicators; 1.3 inspection: convenes the General Manager Office, through