【正文】 近年來，隨著對環(huán)境保護(hù)的重視，高等級公路的邊坡，多采用種草防護(hù)邊坡較高時，采用砌石框格(方型、菱形、拱型、M型)種草防護(hù)。 路基防護(hù) 路基的修筑改變了地層的天然平衡狀態(tài)，以及路基暴露在空間，不斷受各種錯綜復(fù)雜的自然因素侵蝕，因此需要進(jìn)行各種類型的防護(hù)。 地下排水 路基地下排水仍多用暗溝、盲溝、滲溝、滲井等，其特點(diǎn)是以滲透力式排水，當(dāng)水流量較大，多采用帶滲水管的滲溝。普遍采用漿砌片石加固、而水泥混凝土預(yù)制板塊也開始廣泛應(yīng)用。 地面排水 最通常采用適當(dāng)提高路基最小填土高度和地面排水設(shè)施（邊溝、截水溝、跌水、急流槽以及地表的排水管）。 路基排水 水是影響路基強(qiáng)度和穩(wěn)定性及路面的使用壽命的另一重要因素，許多路基病害是由水的侵蝕造成的，另外，從保護(hù)環(huán)境、不損害當(dāng)?shù)剞r(nóng)田水利設(shè)施考慮，也必須做好路基排水，形成排水系統(tǒng)，并與地區(qū)排水規(guī)劃相協(xié)調(diào)。 黃土地區(qū)應(yīng)特別注意路基排水，對地表水應(yīng)采取攔截、分散、防沖、防滲、遠(yuǎn)接遠(yuǎn)送的原則，根據(jù)設(shè)計(jì)及時做好綜合排水設(shè)施，將水迅速引離路基。黃土路堤應(yīng)分層填筑，分層壓實(shí)，大于10cm的塊料，必須打碎，并應(yīng)在接近上的壓實(shí)最佳含水量時碾壓密實(shí)。路床填料不得使用老黃土。摻灰后應(yīng)將土、灰拌勻，其最大干密度應(yīng)通過擊實(shí)試驗(yàn)確定。若地基土層具有強(qiáng)濕陷性或較高的壓縮性，且容許承載力低于路堤自重壓力時，可考慮采用重錘夯實(shí)，墊隔土工布，碎石樁和石灰樁擠密加固的辦法處理。 3，黃土路基填筑及壓實(shí) 黃土路堤施工時，應(yīng)做好填挖界面的結(jié)合(縱向)，清除坡面雜草，挖好向內(nèi)傾斜的臺階。 特殊潮濕地區(qū)路基土的壓實(shí) 在特殊潮濕地區(qū)，路基上的壓實(shí)是相當(dāng)困難的，規(guī)范對此作出了若干調(diào)整：一是壓實(shí)度標(biāo)準(zhǔn)可根據(jù)試驗(yàn)資料確定或較表列數(shù)值降低23個百分點(diǎn)；二是對于天然稠度小于1．1，液限大于40，塑性指數(shù)大于18的粘質(zhì)土，當(dāng)用于下路床及其下的路堤填料時，可采用規(guī)定的輕型壓實(shí)標(biāo)準(zhǔn)；三是改善填料的性質(zhì)，在土中摻加生石灰，通常可以獲得預(yù)期的效果，也可采用新型吸水材料加固。此外，還增加了對路堤基底的壓實(shí)度不宜小于93％的規(guī)定。對于提高路基土的壓實(shí)度起了很好的作用。 ③碾壓速度越高，壓實(shí)效果越差。研究表明，夯擊式機(jī)具的壓力傳遞最深，振動式次之，碾壓式最淺。 壓實(shí)功能對壓實(shí)的影響 同一種土的最佳含水量隨壓實(shí)功能的增加而減少，而最大干密度則隨壓實(shí)功能的增加而增加；當(dāng)含水量一定時，壓實(shí)功能越大則密實(shí)度越高；當(dāng)壓實(shí)功能增加到一定程度后，土的密實(shí)度就增加的不顯著了，這表明，對于某一種土來說，如果超過某一限度，在采用增加壓實(shí)功的辦法來提高土的密實(shí)度就不經(jīng)濟(jì)了。 含水量對壓實(shí)的影響 ①含水量是影響壓實(shí)效果的決定性因素； ②在最佳含水量時，即土處于硬塑狀態(tài)時，最容易獲得最佳的壓實(shí)效果； ③壓實(shí)到最佳密實(shí)度的土體水穩(wěn)性最好。壓實(shí)土基，就是用機(jī)械的方法來改變土的結(jié)構(gòu)，以達(dá)到提高土基強(qiáng)度和穩(wěn)定性的目的。若三者的組成情況發(fā)生改變，則土的物理性質(zhì)亦隨之不同。 壓實(shí)土基地意義 壓實(shí)土基的作用在于提高土體的密實(shí)度，降低土體的透水性，減少毛細(xì)水的上升高度，以防治水分集聚和侵蝕而導(dǎo)致土基軟化，或因凍脹而引起不均勻變形 土基壓實(shí)原理 在絕大多數(shù)情況下，路基土都是由土粒、水分和空氣組成的三相體系。對上路床的的填料提出了限制的條件，高速公路和一級公路路面底以下030cm的路床填料CBR值應(yīng)大于8，下路床及其下面的填土，也都給出相應(yīng)的規(guī)定值。對于液限大于50，塑性指數(shù)大于26的土，一般不宜作為路基填土。填筑路堤的理想材料應(yīng)當(dāng)是穩(wěn)定性好、壓縮性小，便于施工壓實(shí)及運(yùn)距短的土、石材料。從現(xiàn)有條件出發(fā)，改進(jìn)填土要求和壓實(shí)條件是保證路基質(zhì)量最有效和經(jīng)濟(jì)的方法。當(dāng)所有填完之后，可按一般填土進(jìn)行。但坡度較大（橫坡大于1：5）時，應(yīng)將坡面做成臺階，讓填料充分嵌在底基里，以防止路堤的滑移。 坡面基底處理。路堤通過耕地時，路堤填筑施工前必須預(yù)先填平壓實(shí)。若基底的表層土系腐殖土，則需用挖掘機(jī)或人工將表層土清除換填，厚度視具體情況而定，一般不小于30ｃｍ為宜，并予以分層壓實(shí)。 填筑路基時應(yīng)首先進(jìn)行原地面處理。 路基施工過程 原地表及坡面基地處理 路基施工質(zhì)量是整個路線工程的關(guān)鍵也是路基路面工程能否經(jīng)受住時間、車輛行駛荷載、雨季冬季的考驗(yàn)。s gravity retaining wall for stone walls, high and low foundation good occasion, Reinforced concrete structure of cantilever retaining wall, retaining wall and wall of retaining the column is reasonable, wall body WuGong small volume, has been widely used in highway roadbed protection. Enclosed earthretaining wall to adjust the height of the wall, and the prefabricated ponent assembles, is a special type of retaining wall.5 soft foundation treatmentIn recent years, with the highway and level of highway construction, according to the rapid development of soft soil foundation, prevent loss of embankment settlement observational control, stable, soft soil subgrade treatment technology achieved significant results. To deal with the soft soil foundation with sedimentation rate as paving surface subsidence control method to control the time in soft soil foundation, the senior pavement (not pleted the transition of pavement key technical problem solved.limesoil paction pileWhen the content of soft soil layer, take too much or too hours limesoil paction pile.Excessive moisture content can fill in dry soil into holes or lime powder, powder to absorb moisture, or rapid part water hole hole side or under casing hole, or after casing, Moisture content is too small, should be soaked in advance within the scope of reinforcement layer and should be formed after the order, the circle and intervals, Already, should prevent hole by soaking water, and shall be days backfilling ramming, In order to avoid causing shrinkage ramming dozen cold, should play carotid blocking a hole, fill out a hole, When the pile hole, a soft soil, should adopt interval jump play ramming. Packing should be taken before ramming holes punched bottom 34 hammer, According to the test, as with filling pactness, strictly control the ramming material after speed and number, Packing should be returned, and control the white water, Each pore filling dosage should be calculated and plies with the dosage, Should not be less than heavy rammer 100Kg, Hammer type with pear or ZaoHe type more appropriate. To consolidate edge, unfavorable use flat earth fell from general rammer, should be more than 2m, As higher, should reduce groundwater level after backfilling ramming. Already appear, fracture or sandwich, application of luoyang shovel out, all in accordance with the provisions on the grey, fill in ram to meet the design requirements. According to procedures carefully, According to the proportion is weighing, stir evenly to wet, moderation, Each next ash thickness, quantity, and high frequency DWTT according to regulations do consistent test: the construction in strict accordance with the quality evaluation criteria for sampling.Certainly, lightweight embankmentUse of lightweight materials can reduce the embankment of embankment foundation bearing capacity requirements. Currently China has applied the successful experience of fly ash filling embankment, can make the embankment selfrespect reduce 25%. With heavy paction test method for the determination of dry density is 912KN/m3. Silicon ash viscous drilling type, plastic, but not around 64% in liquid limit, the optimum moisture 3741, have good paction performance. Fly ash embankment slope surface with 12m TuBao goo, with the stable slope and grass, road to bed with the top surface coarse closed m thick.geosynthetic materialsShallow (less than 3m thick) of soft soil ground can be used at first, then the roadways perpendicular filling up space, embankment, geotextile filter, drainage and accelerate consolidation, and replace the conventional method of replacement.Soft soil layer 3 was adopted, and sand pad geotextile joint treatment, the thickness of the drainage sand pad by 50cm thinned 30cm. Also in the embankment with surface layers below geotextiles, between laid by materials tensile strength of the sliding deformation to overe foundation stable, through the control filling velocity, cooperate with the foundation for overload rapid consolidation.Using polypropylene and polyethylene geogrid and sub