【正文】 坡面防護(hù) 坡面防護(hù)的目的是防止地表水流的沖刷、坡面巖土的風(fēng)化剝落以及與環(huán)境的協(xié)調(diào)。高速公路和一級公路通過水網(wǎng)地段的路基，過去逢溝設(shè)涵的做法在一些地方有了改進(jìn)，對路線兩側(cè)的灌溉溝渠重新系統(tǒng)布置，免去了穿越路線的排灌涵洞，從而提高了路基的工程質(zhì)量。在路基施工中，應(yīng)重視施工排水，防止因各種原因造成的水患，給路基、路面施工造成不必要的損失。 根據(jù)設(shè)計(jì)及時(shí)修筑外側(cè)邊緣的攔水、截水溝構(gòu)造物和急流槽，將水引至坡腳以外，對高度大于20m的路堤，應(yīng)按設(shè)計(jì)預(yù)留竣工后路堤自重壓密固結(jié)產(chǎn)生的壓縮下沉量。 老黃土透水性差，干濕難以調(diào)節(jié)，大塊土料不易粉碎，使用前應(yīng)通過試驗(yàn)決定措施。如結(jié)合面陡立，無法挖成臺階時(shí)，可采用土工釘加強(qiáng)結(jié)合。如在西部某國道主干線二級專用公路施工中，路面設(shè)計(jì)標(biāo)準(zhǔn)為高級路面，因而從路基開始，所有的檢驗(yàn)標(biāo)準(zhǔn)均采用一級公路驗(yàn)收標(biāo)準(zhǔn)。 當(dāng)前路基施工，普遍采用了大噸位的壓路機(jī)（不小于12t） ，碾壓自路兩邊向中心進(jìn)行，直至表面無明顯輪跡為止，遵循先輕后重、先穩(wěn)后振、先低后高、先慢后快、輪跡重疊的原則，碾壓效果有了明顯的改善。 壓實(shí)工具和方法對壓實(shí)的影響 ①壓實(shí)工具不同，壓力傳遞的有效程度也不同。 影響土基壓實(shí)度的內(nèi)在因素主要是含水量和土的性質(zhì)，外在因素有壓實(shí)功能，壓實(shí)工具和方法等。它們都具有各自的特性，并相互制約共同存于一個(gè)統(tǒng)一體中，構(gòu)成土的各種物理特性滲透性、粘滯性、彈性、塑性和力學(xué)強(qiáng)度等。對路基填料的最小強(qiáng)度和最大粒徑給了量化的標(biāo)準(zhǔn)，采用CBR值表征路基土的強(qiáng)度，引入了路床的概念。 路基填料 規(guī)范規(guī)定了對路基填料應(yīng)有條件的選用。臺階的尺寸，依土質(zhì)、地形＆施工方法而不同，一般寬底不宜小于1m，而且臺階項(xiàng)目應(yīng)做成向堤內(nèi)傾斜3％－5％的坡度，并分層夯實(shí)。如其中有機(jī)質(zhì)含量和其他雜質(zhì)較多時(shí)，碾壓時(shí)因彈性過大，不易壓實(shí)，因換填土或?qū)嵭谢焯睢?yīng)注意將路基范圍內(nèi)的樹根，草叢全部挖除。 路基（土、石方）工程： 質(zhì)量檢查與驗(yàn)收：在檢查及驗(yàn)收時(shí)，應(yīng)著重對路基的壓實(shí)度、平整度、坡度、路基寬度以及彎沉等進(jìn)行檢測。t use silt, swamp, organic soil, frozen, grass, garbage and contain the soil corrosion. More than 50 for liquid limit and plastic index of soil, should not be monly 26 as subgrade filling. The smallest of subgrade filling maximum diameter and strength to quantify the value of the standard, using CBR characterization of subgrade soil strength, introduced the concept of road bed. On the bed of the packing of the condition, highways and highway pavement base class 030cm below the road bed packing should be more than 8, the value of CBR under the bed and the road below, also fill are specified. As subgrade filling cannot reach the minimum strength, should take mixing aggregates, or in filling, or use such as lime stabilization material handling, not for other senior level road paving road, also want to use expressway and the specified level of roads.paction soil baseEarth paction effect of soil paction degree is to improve the permeability of soil, water, reducing the height of capillary, control water and soil erosion of concentration and softening, or because of the yankees and frost heaving the nonuniform deformationearth paction theoryIn most cases, by soil subgrade soil, water and air is posed of threephase system. They all have their respective characteristics and interdependent mon in a unity, constitute the physical characteristics of the soil, viscosity, permeability and elasticity, plasticity and mechanical strength, etc. If the situation changes, is posed of soil physical properties to be different. Therefore, to change the characteristics of soil, and the change from the start. Soil paction, is by mechanical means to change the soil structure, to improve soil base of strength and stability.Earth paction effect of internal factors of soil moisture content and main is nature, external factors have paction function, paction methods and tools, etc.1 paction effect of moisture（1）water is the decisive factor of paction effect,2 when the optimum moisture in the soil, which is hard plastic state, the most easily get the best paction effect,3 the soil pressure ShiDao best density water stability.For soil paction effect(1) the different soil types are different optimum moisture and maximum dry density,2 higher (liquidlimit high dispersion viscosity, the soil, the larger), the absolute best content of absolute maximum dry density and lesser,3 the sand and clay paction of good performance (ρ c ) and cohesive soil paction of poor performance (ρ ) c.paction of paction effect functionThe same kind of soil paction function with the best content decreased, while the maximum dry density function with the paction increases, When the moisture content must, when the paction function is higher density, When the paction increases to a certain function, soil paction degree is not significantly increased, it shows that, for a certain kind of soil, if exceeds a certain extent, in which the paction increases the way to improve soil paction degree is not economical.paction tools and methods for paction effect(1) the paction tools, how effective pressure transmission is different also. Research shows that, after the pressure of machines, vibrationtype transmission deepest, most shallow rolling type.2 the paction machine, load weight more hours long, soil paction degree is higher, but the rate of growth of density decreases with increase of time, paction machine is heavier, soil paction degree was increased with increasing unloading time quickly, but more than a time limit of soil deformation, destruction will increase sharply and achieve, Machines that exceed the soil heavy intensity limit, will cause the soil.3 the higher speed roller paction effect.Currently, generally USES the roadbed construction of largetonnage roller (less than), the road roller upwardleading continuous to center on both sides, until the surface of the wheel track without obvious, follow after the first light weight, low vibration, the first after stability after the first slow, quick, high, the principle of the wheel, paction effect of overlap has been improved. To improve the subgrade soil paction degree on the good effect. Rules and regulations and highway pavement under the bottom 80 more on the part of the subgrade paction degree of other must 94%, senior level road paving road, when the paction degree also should press expressway and the level of roads by the standard. In addition, also increases the base of subgrade paction degree should not be less than 93% of regulation. As a main road in the west of highway construction, secondary specialized standard for senior road pavement design, from the beginning, all roadbed inspection standards adopted grade highway acceptance criteria.special damp area of subgrade soil pactionIn special areas damp, the roadbed paction is very difficult to make some adjustment standard: one is the degree of paction test data can be determined according to the standard list or lower numerical reduce 23 percentage points, Two is less than , natural consis