本文關(guān)鍵詞：平原水網(wǎng)地區(qū)低路堤高速公路路基動力特性研究　出處：《中南大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 低路堤 交通荷載 動力測試 數(shù)值分析

【摘要】：高速公路低路堤設(shè)計具有節(jié)約土地資源、節(jié)省投資、施工方便、行車安全、景觀協(xié)調(diào)、路基病害少等優(yōu)點。同時降低路堤高度也有其弊端,主要有：低路堤易受地下水滲透和地表水沖刷；路堤高度降低造成交通荷載無法充分?jǐn)U散傳遞至地基,從而加劇地基沉降變形。此外,交通動荷載振動也易引起地基不均勻沉降。這些問題可以歸結(jié)為水、交通荷載對路基的作用問題。因此,如何分析交通荷載對低路堤路基的影響就是急需解決的關(guān)鍵技術(shù)問題。本研究以此為著眼點,重點從以下幾個方面研究交通荷載作用下路基的動力響應(yīng)對路基狀態(tài)影響： (1)首先通過對國內(nèi)外資料的調(diào)研,掌握了交通動荷載對路基的主要影響及其機(jī)理,明確研究此類影響所需的手段和方法,在此基礎(chǔ)上提出低路堤路基研究存在的主要不足和改進(jìn)方法。 (2)提出了交通荷載對低路堤影響的現(xiàn)場試驗方法。該方法采用原位測試技術(shù),以實際通過車輛為振源,測試內(nèi)容包括路面振動、路基路面內(nèi)部結(jié)構(gòu)動力響應(yīng)等,并重點介紹了測試元件埋設(shè)方案,方案包括測試位置的選取、適用元件的性能、埋設(shè)技術(shù),可作為今后類似實驗的參考。 (3)現(xiàn)場測試獲取了不同車輛荷載經(jīng)過路面時引起的路面各結(jié)構(gòu)層、路床以及路表面的動應(yīng)力、動應(yīng)變、振動加速度、動位移等振動數(shù)據(jù),分析認(rèn)為,路基頂面動應(yīng)力沿深度方向衰減,距路面頂面0.7m處動應(yīng)力衰減達(dá)60%；公路各結(jié)構(gòu)層動應(yīng)力隨著交通荷載的增加線性增大；路面動位移的時域波形主要由低頻率組成,且主要受車輛載重影響。路面結(jié)構(gòu)層動態(tài)響應(yīng)隨速度的增加而減小,而應(yīng)力變化隨著載重的增加而增加的。 (4)依據(jù)試驗段現(xiàn)場資料建立有限元計算模型,以補(bǔ)充測試試驗無法獲取的路基動力響應(yīng)狀態(tài)。分析得到,當(dāng)采用標(biāo)準(zhǔn)120kN幅值加載時,交通動載影響深度在2.5m范圍以內(nèi)比較明顯,振動加速度影響范圍在5.5m以內(nèi)；隨荷載幅值增加動應(yīng)力隨之增加；交通荷載相同條件下,路堤高度影響明顯,隨高度降低路基沉降增加明顯；但路面模量的增加對沉降影響較小。
[Abstract]:Freeway low embankment design has the advantages of saving land resources, saving investment, convenient construction, traffic safety, landscape coordination, the advantages of roadbed diseases. At the same time reduce the height of embankment has its defects, are susceptible to low embankment seepage of groundwater and surface water erosion; Lu Digao degree reduces the traffic load can not fully transfer to the ground so as to spread. Increase the settlement. In addition, traffic load vibration may cause uneven settlement of foundation. These problems can be attributed to water, traffic load on the subgrade effect. Therefore, the key technical problem of how to analyze the impact of traffic load on low embankment is urgent. Based on this starting point, focuses on the influence on the roadbed dynamic response of Subgrade under traffic loads from the following aspects:
(1) first, through investigating the data at home and abroad, we have grasped the main influence and mechanism of the traffic dynamic load to the roadbed, and clearly defined the means and methods needed to study such influence. Based on that, we put forward the main shortcomings and improvement methods of the research of low embankment Subgrade.
(2) proposed field test method for effect of traffic load on low embankment. The method using in situ testing technology, to the actual vehicle through Zhenyuan, test content including pavement vibration, dynamic response of subgrade and pavement structure, and introduces the test element embedment scheme, including the selection of test scheme of position, performance, applicable elements the embedded technology, can be used as a reference for future similar experiments.
(3) field test to obtain different vehicle load caused by pavement pavement after each layer of roadbed and road surface dynamic stress, dynamic strain, vibration acceleration, dynamic displacement and vibration data analysis, subgrade dynamic stress attenuation along the depth direction, away from the pavement surface 0.7m dynamic stress the attenuation of 60%; every road structural layer dynamic stress with the traffic load increases linearly; time domain waveform of pavement dynamic displacement is mainly composed of low frequency components, which is mainly affected by vehicle load. The dynamic response of pavement structure layer decreases with the increase of speed, and the stress variation increases with load increasing.
(4) on the basis of field data of test section of the finite element model was established to test the dynamic response of Subgrade of state cannot be obtained. Results show that when using standard 120kN amplitude loading and traffic dynamic load influence depth is more obvious in the range of 2.5m, the vibration acceleration influence range within 5.5m; dynamic stress increases with the the load amplitude increased; the traffic load under the same condition, influence of embankment height obviously decrease with height of subgrade settlement increased significantly; but the pavement modulus increased on the settlement of little effect.

【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U416.1

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本文編號：1399399