【正文】 急變“駝峰式縱坡”。“斷背曲線”。首先是試坡，試坡以“控制點(diǎn)”為依據(jù)，考慮平縱結(jié)合、挖方、填方以及排水溝設(shè)置等眾多因素初步擬訂坡度線。,，,，4＝15m，2=，2=，中間帶的寬度為3m(，2=)瀝青混凝土及水泥混凝土路拱坡度均為1~2%，故取路拱坡度為2%；路肩橫向坡度一般應(yīng)較路面橫向坡度大1%~2%，故取路肩橫向坡度為3%，路拱坡度采用雙向坡面，由路中央向兩側(cè)傾斜。，示出土石界限、設(shè)計(jì)邊坡度，并確定邊溝形狀和尺寸。因此，超高橫坡度在圓曲線上應(yīng)是與圓曲線半徑相適應(yīng)的全超高，在緩和曲線上應(yīng)是逐漸變化的超高。雙坡階段：曲線內(nèi)側(cè)行車道邊緣：hil=(bl+bx)il （）硬路肩邊緣：hi2=hil+b2i2 （）土路肩邊緣：hi3=hi2+b3i3 （）曲線外側(cè)行車道邊緣：hol=(2x/xo1)blil （）硬路肩邊緣：ho2=holb2i2 （）土路肩邊緣：ho3=ho3b3i3 （）。一般采用分段調(diào)用。路基基底為耕地或土質(zhì)松散時(shí)，應(yīng)在填前進(jìn)行壓實(shí)，路基設(shè)計(jì)時(shí)，可考慮了清理場(chǎng)地后進(jìn)行填筑壓實(shí)。：1) 路床土質(zhì)應(yīng)均勻、密實(shí)、強(qiáng)度高，上路床壓實(shí)度達(dá)不到要求時(shí)，必須采取晾曬，摻石灰等技術(shù)措施。5) 路基土的摻灰劑量，可根據(jù)當(dāng)?shù)厍闆r實(shí)驗(yàn)確定，一般粘質(zhì)土采用石灰或二灰處理，粗粒土可以采用25號(hào)水泥處理。本公路的路面排水主要由攔水帶、急流槽和路肩排水溝以及中央分隔帶排水設(shè)施組成。3) 矩形雨水井尺寸采用長寬深=60cm40cm60cm，邊墻采用漿砌片石或水泥混凝土預(yù)制塊砌筑。當(dāng)路肩墻與路堤墻的墻高或截面圬工數(shù)量相近，基礎(chǔ)情況相似時(shí)，應(yīng)優(yōu)先選用路肩墻，按路基寬布置擋土墻位置，因?yàn)槁芳鐡跬翂沙浞质湛s坡腳，大量減少填方和占地。擋土墻縱向布置在墻趾縱斷面圖上進(jìn)行，布置后繪成擋土墻正面圖。，包括數(shù)量、間隔和尺寸等。當(dāng)風(fēng)化層較厚難以全部清除時(shí)，可根據(jù)地基的風(fēng)化程度及其容許承載力將基底埋入風(fēng)化層中。為防止水分滲入地基，下排泄水孔進(jìn)水口的底部應(yīng)鋪設(shè)30cm厚的粘土隔水層。當(dāng)軸間距離大于3m時(shí)，按單獨(dú)的一個(gè)軸載計(jì)算；當(dāng)軸間距離小于3m時(shí)，應(yīng)考慮軸數(shù)系數(shù)。各層材料的劈裂強(qiáng)度：。規(guī)范規(guī)定高速公路一級(jí)公路的面層由二至三層組成，查規(guī)范，采用二層瀝青面層，表面層采用細(xì)粒式密級(jí)配瀝青混凝土（厚4cm），中面層采用中粒式密級(jí)配瀝青混凝土（厚8cm）。計(jì)算二灰土底基層容許彎拉應(yīng)力：，∴故該路面結(jié)構(gòu)符合要求。路基回彈模量取30MPa，石灰粉煤灰穩(wěn)定土墊層回彈模量取600MPa，水泥穩(wěn)定粒料基層回彈模量取1300MPa。 方案二：，底基層選用水泥穩(wěn)定粒料（水泥用量5%）。普通混凝土面層的荷載疲勞應(yīng)力計(jì)算：碾壓混凝土基層的荷載疲勞應(yīng)力計(jì)算： 溫度疲勞應(yīng)力計(jì)算：IV6區(qū)最大溫度梯度?。?2℃/m）。路基回彈模量取30MPa，石灰粉煤灰穩(wěn)定土墊層回彈模量取600MPa，水泥穩(wěn)定粒料基層回彈模量取1300MPa。對(duì)水泥砼路面和瀝青砼路面兩種方案比較如下表：比較項(xiàng)目瀝青路面水泥砼路面使用壽命設(shè)計(jì)年限15年，可通過維修延長使用年限設(shè)計(jì)年限30年造 價(jià)低稍高平坦性及震動(dòng)噪音行車舒適、噪音和震動(dòng)小產(chǎn)生接縫震動(dòng)、噪音稍大明色性路面反光能力弱，視覺柔和路白光較強(qiáng)，視覺效果差施工性受環(huán)境因素影響小，施工進(jìn)度快受外界影響大，養(yǎng)生期長，工期長抗變形能力及耐磨性材料選擇不當(dāng)時(shí)易產(chǎn)生車轍，耐磨性差，寒地易出現(xiàn)裂縫難以產(chǎn)生車轍變形，耐磨性強(qiáng)，基層壓實(shí)度不均勻時(shí)易產(chǎn)生裂縫維修難易養(yǎng)護(hù)維修工藝簡單維修規(guī)模大，復(fù)雜地下管線維修及增設(shè)便于地下管線維修與增設(shè)不便于管線維修、增設(shè)，路面不易恢復(fù)，費(fèi)用高水泥混凝土路面的特點(diǎn)：它是一種剛度大；擴(kuò)散荷載應(yīng)力的能力強(qiáng)；穩(wěn)定性好和使用壽命長的路面結(jié)構(gòu)，和其他路面結(jié)構(gòu)相比有以下優(yōu)點(diǎn)：強(qiáng)度高，穩(wěn)定性好，受水的漫入和氣候溫度等自然因素影響時(shí)，引起的強(qiáng)度變化小，耐久性好，養(yǎng)護(hù)維修費(fèi)用小，抗滑性能好，有利于夜間行車等。s democratic revolution, the great forerunner Dr. Sun Yatsen once said : The roads were also the mother of civilization. Pulse also wealth, the concept trial today civilized nations that most country roads. Thus, highway on the national economy. people39。s the later period, is the adaption economy develops and develops the border area the need, our country starts the largescale construction to lead to the border area and the mountainous area road, has constructed the ChengduLhasa Highway, the QinghaiTibet Highway one after another, and in the southeast coast, northeast and southwest the local construction national defense highway, the road course rapid growth, in 1959 amounted to more than500,000 kilometers.The 6039。s highway construction experiencing a basic adaptation of national economic developmentnot suited to the development of the national economyconstraining the development of the national economy constraints on the national economy marked improvement process. Economic development, transportation first, its validity for the whole society has been proven by the practices. Therefore, pletely changed our transport and the backward state of the passive situation, is the progressive realization of the modernization of China39。s endachieved 890,000 kilometers, the average increased approximately30,000 kilometers every year, the road density achieved 9. 3 kilometers hundred square kilometers. After the reform and opening up road infrastructure building and achievements. After the reform and opening up, the national economy continued its rapid development, road transport demand is robust growth, Highway infrastructure construction began a historic changes, and its main features : Highway construction of the central and local levels, the attention of the government, If you want to get rich, the first road, Highway construction of the importance of gradually recognized by the whole society. In the basis of unified planning, started a program of the National Highway infrastructure construction, the early 1980s and late 1980s, national trunk highway network and the National Road Route Planning System has drawn up and implemented, Highway building with a clear overall goals and milestones. Highway construction continued to expand the overall size, while focusing on the strengthening of quality improvement, Expressway and other highgrade highways to develop rapidly. The country39。s road constructions are facing severe challenges. In the national economy continued its rapid growth and urbanization process will continue to accelerate the process, various cities facing redevelopment, transformation, expansion and replanning, and road infrastructure building is the present and future urban development. Highway understanding of the history and development of the status quo, for how we sustained development of the national economy based on the strategic goals the development and planning of the new era of highway construction in the sustainable development strategy is very important. 1. A modern highway39。路面結(jié)構(gòu)面層采用瀝青混凝土15cm、基層采用水泥碎石25cm、底基層采用石灰土15cm。 荷載疲勞應(yīng)力計(jì)算為：溫度疲勞應(yīng)力計(jì)算： 查規(guī)范可知，IV6區(qū)最大溫度梯度取92℃。確定可靠度系數(shù)普通混凝土面層碾壓混凝土基層，可以承受設(shè)計(jì)基準(zhǔn)期內(nèi)荷載應(yīng)力和溫度應(yīng)力的綜合疲勞作用。此時(shí)。荷載疲勞應(yīng)力計(jì)算為：溫度疲勞應(yīng)力計(jì)算： 查規(guī)范可知，IV6區(qū)最大溫度梯度取92℃。： 根據(jù)表設(shè)計(jì)規(guī)范，高速公路的設(shè)計(jì)基準(zhǔn)期為30年，安全等級(jí)為一級(jí)，~，則：其交通量在中，故屬重型交通。設(shè)計(jì)彎沉值計(jì)算：對(duì)于高速公路，規(guī)范要求以設(shè)計(jì)彎沉值作為設(shè)計(jì)指標(biāo)，并進(jìn)行結(jié)構(gòu)層底拉應(yīng)力驗(yàn)算。設(shè)計(jì)彎沉值：各層材料容許層底拉應(yīng)力：細(xì)粒式密級(jí)配瀝青混凝土：中粒式密級(jí)配瀝青混凝土：粗粒式密級(jí)配瀝青混凝土：水泥碎石：石灰土：設(shè)計(jì)彎沉值為23（），查有關(guān)資料的表格得各層材料抗壓模量（20℃）與劈裂強(qiáng)度（20℃）與劈裂強(qiáng)度表材料名稱H（cm）20℃抗壓模量（MPa）劈裂強(qiáng)度容許拉應(yīng)力（MPa）細(xì)粒式瀝青混凝土41400中粒式瀝青混凝土51200粗粒式瀝青混凝土61000水泥碎石基層251500石灰土待定550土基—38——：H(m)材料名稱20℃抗壓模量（MPa）4cm細(xì)粒式瀝青混凝土14005cm中粒式瀝青混凝土12006cm粗粒式瀝青混凝土100025cm水泥碎石1500待定石灰土550土基確定石灰土的厚度（換算成三層體系）：令理論彎沉值等于設(shè)計(jì)彎沉值：，其中： 令LR= ∴查規(guī)范得 ∴查規(guī)范得∴∴查表得： ∴根據(jù)∴ 取彎拉應(yīng)力的驗(yàn)算：瀝青混凝土頂層 = ,