【摘要】：路基是路面結(jié)構(gòu)的基礎(chǔ),但在長期的運營過程中,受外界水分、荷載等因素的影響,路基土的耐久性會發(fā)生變化,主要表現(xiàn)為強度的衰減,從而引起路面結(jié)構(gòu)的破壞。在路基與半剛性基層間設(shè)置過渡層,可有效緩解路基病害對路面結(jié)構(gòu)的影響,但目前尚沒有系統(tǒng)的設(shè)計方法針對過渡層的厚度、材料等進行專門的設(shè)計。因此,本文從研究路基土的耐久性特征及其對路面結(jié)構(gòu)的影響出發(fā),基于過渡層的作用機理,對路基與半剛性基層間的過渡層的設(shè)計方法進行研究。 水分是影響路基土耐久性的主要因素,而細粒土具有較強的持水能力,其性質(zhì)更易受水分的影響。論文首先通過室內(nèi)試驗?zāi)M粉土和粘土內(nèi)部水分的滲透作用和毛細上升作用,在此基礎(chǔ)上,對比分析土質(zhì)對水分遷移規(guī)律的影響,以及不同類型土的耐久性變化特征；其次針對在不同交通量情況下路基含水率較高而誘發(fā)的路面病害進行調(diào)查,總結(jié)出路基土耐久性變化引起的路面病害的主要形式；最后結(jié)合路用環(huán)境定量分析路基耐久性不足引起的路面結(jié)構(gòu)疲勞壽命的衰減幅度,計算結(jié)果與實際情況相符。 路基土的回彈模量是路面結(jié)構(gòu)設(shè)計的重要參數(shù),也是反映路基土耐久性的主要指標。論文首先分析路基土的應(yīng)力依賴性和水敏感性,并根據(jù)土水特征曲線,以基質(zhì)吸力為媒介,建立路基土回彈模量的應(yīng)力依賴性和水敏感性耦合模型,且通過室內(nèi)試驗進行驗證;其次結(jié)合實際環(huán)境中外部荷載和路基內(nèi)部水分的變化,分析運營期間路基土回彈模量的變化趨勢；最后將“動態(tài)”的交通量與“靜態(tài)”的軸載進行相互轉(zhuǎn)化,提出我國半剛性基層瀝青路面典型結(jié)構(gòu)在不同交通量等級下的容許最小路基強度。 彈性層狀體系理論是我國路面結(jié)構(gòu)設(shè)計的基礎(chǔ)理論。論文首先結(jié)合彈性層狀體系的力學響應(yīng)特征,研究厚度、模量等結(jié)構(gòu)參數(shù)變化對各結(jié)構(gòu)層受力的影響,分析影響彈性層狀體系內(nèi)部各結(jié)構(gòu)層受力的直接因素,從理論上提出設(shè)置過渡層可以有效改善路基強度衰減對路面結(jié)構(gòu)的影響；其次研究過渡層的作用機理,主要包括對下層結(jié)構(gòu)的補強作用和對上層荷載的削弱作用,并分析過渡層的厚度、模量等結(jié)構(gòu)參數(shù)對其作用的影響；最后依據(jù)補強作用原理,建立補強后當量模量的預(yù)估模型,并提出基于補強遞增系數(shù)的的最佳補強理論和經(jīng)濟模量,既能滿足結(jié)構(gòu)的力學性能要求,又能充分利用過渡層的強度。 級配碎石既有一定的強度又能適應(yīng)一定的變形,是作為過渡層的理想材料,合理的級配是保證級配碎石過渡層的路用性能的重要前提。論文首先對目前常用的級配設(shè)計方法進行分析,其本質(zhì)是分形理論的不同應(yīng)用形式,并提出集料的分形特征；然后對目前各國規(guī)范中級配碎石的分形特征進行分析,依據(jù)固體體積率、CBR、二次松散系數(shù)等路用性能等進行優(yōu)化,提出適用于過渡層的級配碎石的級配范圍,并與我國規(guī)范中規(guī)定的級配范圍進行性能對比,檢驗級配碎石分形級配范圍的合理性。 論文結(jié)合高含水率粉土路基路段的公路大修工程,對級配碎石過渡層的設(shè)計及應(yīng)用進行說明。首先,對路面病害類型及主要成因進行詳細分析,認為路基土耐久性衰減是引起路面損壞的主要原因,符合過渡層的設(shè)置條件；其次,結(jié)合現(xiàn)場交通量條件利用最佳補強理論對級配碎石過渡層的厚度和模量進行設(shè)計,并能夠滿足結(jié)構(gòu)驗算的要求；最后,總結(jié)出級配碎石的施工工藝及質(zhì)量檢驗標準。
[Abstract]:The subgrade is the foundation of the pavement structure, but during the long-term operation, the durability of the subgrade soil can change due to the influence of the external water and the load. The main performance is the attenuation of the strength, thus causing the damage of the pavement structure. The transitional layer is set between the subgrade and the semi-rigid base layer, and the effect of the roadbed disease on the pavement structure can be effectively relieved, but the design method of the system is not currently designed for the thickness and the material of the transition layer. Therefore, from the study of the durability of the subgrade soil and its influence on the pavement structure, the paper studies the design method of the transition layer between the subgrade and the semi-rigid base layer based on the action mechanism of the transition layer. Water is the main factor that affects the durability of the subgrade soil, and the fine-grained soil has strong water-holding capacity, and its properties are more susceptible to water. In this paper, the effects of soil quality on the law of water migration and the durability of different types of soil are compared. The main shape of the road surface disease caused by the change of the durability of the subgrade soil is summarized, and the road surface diseases induced by the high water content of the subgrade under different traffic conditions are investigated. formula; the final combined road is used for quantitatively analyzing the attenuation amplitude of the fatigue life of the pavement structure caused by the insufficient durability of the subgrade, and the calculation result is compared with the actual situation; The resilience modulus of the subgrade soil is an important parameter of the pavement structure design, and is the main part of the durability of the subgrade soil. In this paper, the stress-dependence and water-sensitivity of the subgrade soil are analyzed firstly, and the stress-dependent and water-sensitive coupling model of the resilience modulus of the subgrade soil is set up according to the soil water characteristic curve, and the stress-dependent and water-sensitive coupling model of the subgrade soil resilience modulus is established. Line verification; secondly, according to the external load in the actual environment and the change of water in the subgrade, the change trend of the rebound modulus of the subgrade soil during operation is analyzed; and finally, the traffic volume of the 鈥渄ynamic鈥，

本文編號：2392409