發(fā)布時(shí)間：2018-05-09 18:37

  本文選題：粒料基層 + 永久變形��； 參考：《東南大學(xué)》2015年博士論文

【摘要】：限制粒料基層瀝青路面結(jié)構(gòu)的永久變形是路面結(jié)構(gòu)設(shè)計(jì)的一項(xiàng)基本要求,也是此類路面結(jié)構(gòu)設(shè)計(jì)方法普遍選取的一種損壞模式。本文主要針對粒料層的永久變形開展研究,目的是提出控制粒料層永久變形的設(shè)計(jì)指標(biāo),并建立相應(yīng)的控制模型,主要工作包括以下幾個(gè)方面：首先,選定141種典型路面結(jié)構(gòu)進(jìn)行粒料層應(yīng)力水平分析,并對半剛性基層+粒料層倒裝結(jié)構(gòu)與粒料基層全柔性結(jié)構(gòu)兩種典型結(jié)構(gòu)43種組合進(jìn)行分析,對各結(jié)構(gòu)層厚度與模量變化對粒料層應(yīng)力水平影響進(jìn)行分析,得到了各因素對粒料層應(yīng)力狀態(tài)的影響規(guī)律,提出了適宜的粒料層厚度范圍與下臥層模量要求；確定了粒料基層典型應(yīng)力水平σ1=100-250kPa, σ3=0～100kPa,主應(yīng)力比在σ1/σ3=1.2～7.9,主要分布在1.4～5.1之間,從而確定了動態(tài)模量加載序列和永久變形試驗(yàn)加載條件。第二,以動態(tài)模量和CBR為級配碎石材料設(shè)計(jì)性能參數(shù),研究了不同含水量、不同應(yīng)力狀態(tài)與不同壓實(shí)度對動態(tài)模量的影響,得到了不同級配的影響規(guī)律以及不同層位粒料層模量取值范圍；控制關(guān)鍵篩孔不同級配動態(tài)模量與CBR的變化,對級配碎石級配組成進(jìn)行優(yōu)化,得到了關(guān)鍵篩孔控制通過率。采用貝雷法對級配參數(shù)進(jìn)行了嵌擠狀態(tài)判定,得到了骨架嵌擠狀態(tài)下CA的取值范圍。第三,分析了主應(yīng)力比、圍壓、級配及含水量對永久變形特性的影響規(guī)律,永久變形在1000次加載時(shí)已基本形成,20000次以后變形累積非常緩慢；依據(jù)試驗(yàn)結(jié)果對M-E模型參數(shù)進(jìn)行了回歸分析,另外,重新構(gòu)建了基于應(yīng)力狀態(tài)的永久應(yīng)變預(yù)估模型,并提出了含水量的調(diào)節(jié)系數(shù)；第四,論證了粒料層永久變形試驗(yàn)方案,采用30kPa、50kPa和70kPa三個(gè)圍壓,不同主應(yīng)力比作為應(yīng)力加載路徑永久變形試驗(yàn)。分析了不同應(yīng)力加載路徑下的永久變形特性,并利用非線性統(tǒng)計(jì)回歸和Perez,Ⅰ.模型對試驗(yàn)曲線進(jìn)行了外延,確定以永久軸向應(yīng)變速率不大于1×10-5/10-3(每個(gè)加載周期)時(shí),做為粒料的永久變形處于A-B區(qū)域邊界(安定限界)的判斷準(zhǔn)則。最后,計(jì)算了162種典型路面結(jié)構(gòu)的粒料層永久變形量,分析了各路面結(jié)構(gòu)層所占路面結(jié)構(gòu)總永久變形量的比例,擬定了6mm做為臨界永久變形量標(biāo)準(zhǔn),確定室內(nèi)試驗(yàn)臨界永久應(yīng)變?yōu)?.03,調(diào)整了粒料層永久變形占總變形的比例。利用外延永久變形試驗(yàn)曲線,得到臨界塑性應(yīng)變標(biāo)準(zhǔn)對應(yīng)的標(biāo)準(zhǔn)荷載作用次數(shù)。提出了以應(yīng)力比(垂直應(yīng)力與圍壓)作為控制粒料基層永久變形的設(shè)計(jì)指標(biāo),建立了基于4.75mm關(guān)鍵篩孔的永久變形的控制模型。本文以安定理論作為理論基礎(chǔ),尋找粒料永久變形處于塑性安定與塑性蠕變時(shí)的臨界應(yīng)力比,建立粒料基層永久變形處于塑性安定狀態(tài)下的控制模型,使設(shè)計(jì)的路面結(jié)構(gòu)在荷載周期內(nèi)處于塑性安定狀態(tài),而不產(chǎn)生過大的永久變形,對粒料基層柔性路面結(jié)構(gòu)設(shè)計(jì)與應(yīng)用具有重要意義。
[Abstract]:Limiting the permanent deformation of asphalt pavement structure of granular base is a basic requirement of pavement structure design, and it is also a kind of damage mode which is generally selected by this kind of pavement structure design method. The purpose of this paper is to put forward the design index of controlling the permanent deformation of granular layer and to establish the corresponding control model. The main work includes the following aspects: first, 141 typical pavement structures are selected to analyze the stress level of granular layer, and 43 kinds of typical structures are analyzed, such as reverse structure of semi-rigid base granular layer and fully flexible structure of granular base. The influence of the thickness and modulus of each structure layer on the stress level of the granular layer is analyzed. The influence law of each factor on the stress state of the granular layer is obtained, and the suitable thickness range of the granular layer and the requirement of the underlying layer modulus are put forward. The typical stress levels of granular base are determined as 蟽 _ 1 ~ 100 ~ 250 KPA, 蟽 _ 3 ~ 0 ~ (100) KPA, the principal stress ratio is 蟽 _ 1 / 蟽 _ (3) 1.2g ~ (7.9), and the main distribution is between 1.4 ~ 5.1. The loading sequence of dynamic modulus and the loading condition of permanent deformation test are determined. Secondly, the effects of different water content, different stress state and different compaction degree on dynamic modulus are studied with dynamic modulus and CBR as the design parameters of graded macadam. The influence law of different gradation and the value range of modulus of different horizon granular layer are obtained, the dynamic modulus of different gradation of key sieve hole and the change of CBR are controlled, the gradation composition of gradation gravel is optimized, and the control pass rate of key sieve hole is obtained. Bayley method is used to judge the inlay state of gradation parameters, and the value range of CA in skeleton embed state is obtained. Thirdly, the effects of principal stress ratio, confining pressure, gradation and water content on the permanent deformation characteristics are analyzed. After 1000 times of loading, the accumulation of deformation is very slow. According to the test results, the parameters of M-E model are regressed, in addition, the permanent strain prediction model based on stress state is constructed, and the adjustment coefficient of water content is put forward. Three confining pressures, 30 KPA 50 KPA and 70kPa, were used to test the permanent deformation of stress loading paths with different principal stress ratios. The characteristics of permanent deformation under different stress loading paths are analyzed, and nonlinear statistical regression and Perez, 鈪，

本文編號：1866973