【摘要】：我國活斷層廣泛分布,近年來快速城鎮(zhèn)化使得城鎮(zhèn)規(guī)模不斷擴(kuò)大,工業(yè)與民用建筑、地鐵與輸油管線等城市生命線工程不可避免地鄰近或跨越斷層。斷層錯(cuò)動(dòng)引起上覆土層破裂,對地表建筑物、地下管線和隧道等結(jié)構(gòu)物造成巨大破壞,使人民生命財(cái)產(chǎn)安全受到嚴(yán)重威脅。本文采用常重力模型試驗(yàn)方法研究了逆斷層錯(cuò)動(dòng)作用下上覆砂土層的變形特征和破裂帶擴(kuò)展規(guī)律。主要研究工作包括： (1)研制了模擬斷層錯(cuò)動(dòng)引起上覆土層破裂過程的常重力模型試驗(yàn)裝置。該裝置可實(shí)現(xiàn)錯(cuò)動(dòng)速率0～6mm/s、5個(gè)傾角(30/45/60/75/90°)的逆斷層和正斷層錯(cuò)動(dòng),模型土層厚度最大可達(dá)600mm。 (2)提出了采用PIV技術(shù)量測斷層錯(cuò)動(dòng)過程中上覆土體位移和應(yīng)變的方法,實(shí)現(xiàn)了斷層錯(cuò)動(dòng)過程中地表隆起(沉陷)、上覆土層主剪切區(qū)變形及土體破裂過程的精確刻畫。 (3)開展了9組逆斷層錯(cuò)動(dòng)模型試驗(yàn),研究了逆斷層錯(cuò)動(dòng)作用下上覆砂土層破裂過程、地表隆起變形及土層剪切變形,對比分析了斷層錯(cuò)動(dòng)速率、土層厚度、土體密實(shí)度、場地傾斜對上覆土層變形特征和破裂帶擴(kuò)展規(guī)律的影響。試驗(yàn)結(jié)果表明： 1)逆斷層錯(cuò)動(dòng)過程中,上覆土層先后出現(xiàn)主、次2條破裂帶。主破裂帶起始擴(kuò)展角與斷層傾角一致,在向上發(fā)展過程中逐漸偏向下盤。當(dāng)斷層豎向位移達(dá)到土層厚度的5%左右時(shí),主破裂帶出露地表,此時(shí)擴(kuò)展角β與土體內(nèi)摩擦角Φ和地表傾角γ(以與斷層傾角同向?yàn)檎?滿足β=45°-Φ/2+γ的關(guān)系。 2)逆斷層錯(cuò)動(dòng)作用下,上覆土層可劃分成三個(gè)變形區(qū),即下盤的“靜態(tài)區(qū)”、上盤的“剛性區(qū)”和破裂帶附近的“主剪切區(qū)”。主剪切區(qū)總體呈偏向上盤的倒三角形。隨著錯(cuò)動(dòng)位移量增加,主剪切區(qū)向上發(fā)展,主剪切區(qū)地表寬度非線性增長,且增長速率隨錯(cuò)動(dòng)位移量增加而減小。 3)地表隆起隨著斷層錯(cuò)動(dòng)量增加而增大,最大地表坡度和坡度大于等于1/150的影響范圍也逐漸增加,并最終趨于定值。當(dāng)斷層傾角為60°時(shí),地表受影響范圍約為土層厚度的1.0～1.3倍。 4)逆斷層錯(cuò)動(dòng)試驗(yàn)速率(0.05/0.16/0.50mm/s)和土層厚度(200/400/600mm)對上覆土層破裂規(guī)律的影響不明顯；土體密實(shí)度越大,破裂帶出露地表所需的豎向錯(cuò)動(dòng)位移越小,主剪切區(qū)和地表受影響區(qū)越小,但地表最大坡度和破裂帶水平傳播距離越大。 5)場地地表傾角γ對土層剪切變形和破裂帶擴(kuò)展有重要影響。隨著地表傾角增大,破裂帶出露地表所需的豎向錯(cuò)動(dòng)位移增大,破裂帶水平傳播距離減小。無論地表傾角γ由0°減小至-5°還是由0°增大至5°,均會導(dǎo)致地表陡坎最大坡角變大,地表受影響區(qū)域?qū)挾茸兇蟆?br/>[Abstract]:Active faults are widely distributed in China. In recent years rapid urbanization has made the scale of cities and towns expand constantly. Urban lifeline projects such as industrial and civil buildings subway and oil pipelines inevitably close to or cross faults. The fault dislocation causes the rupture of the overlying soil layer, which causes great damage to the structures such as surface buildings, underground pipelines and tunnels, which seriously threatens the safety of people's lives and property. In this paper, the deformation characteristics and fracture zone propagation of the overlying sand layer used in the reverse fault dislocation action are studied by using the method of constant gravity model test. The main research works are as follows: (1) A constant gravity model test device is developed to simulate the rupture process of overlying soil caused by fault dislocation. The device can realize the reverse fault and normal fault dislocation of 0 or 6 mm / s, 5 dip angles (30 / 45 / 60 / 75 / 90 擄), and the maximum thickness of the model soil layer can be up to 600mm. (2) the method of measuring the displacement and strain of the overlying soil in the process of fault dislocation by using PIV technique is put forward. The accurate description of surface uplift (subsidence), deformation of the main shear zone of overlying soil and the process of soil failure in the process of fault dislocation has been realized. (3) Nine sets of reverse fault dislocation model tests have been carried out. In this paper, the fracture process of overlying sand layer, surface uplift deformation and shear deformation of soil layer are studied. The fault dislocation rate, the thickness of soil layer and the compactness of soil are compared and analyzed. Effects of site tilt on deformation characteristics and fracture zone expansion of overlying soil. The experimental results show that: 1) in the process of reverse fault dislocation, there are two main and secondary rupture zones in the overlying soil layer. The initial spreading angle of the main fracture zone is consistent with the fault dip angle, and gradually deviates to the lower side during the upward development. When the vertical displacement of the fault reaches about 5% of the thickness of the soil layer, the main rupture zone is exposed to the surface. At this time, the extension angle 尾 and the internal friction angle 桅 of soil and the surface dip angle 緯 (positive to the dip angle of the fault) satisfy the relation of 尾 = 45 擄- 桅 / 2 緯. 2) the overlying soil can be divided into three deformation zones, that is, the "static zone" of the lower face. The "rigid zone" of the upper disc and the "main shear zone" near the rupture zone. In general, the main shear zone is an inverted triangle with a bias to the upper disc. With the increase of the dislocation displacement, the main shear zone develops upward, the surface width of the main shear zone increases nonlinear, and the growth rate decreases with the increase of the dislocation displacement. 3) the surface uplift increases with the increase of fault momentum. The influence range of the maximum surface slope and slope greater than or equal to 1 / 150 increases gradually and tends to a constant value. When the fault dip angle is 60 擄, the affected area of the surface is about 1.0 ~ 1.3 times of the thickness of the soil layer.) the effect of 0.05/0.16/0.50mm/s and 200/400/600mm on the rupture of the overlying soil layer is not obvious, and the density of the soil is larger. The smaller the vertical dislocation displacement required for the rupture zone out of the exposed surface, the smaller the main shear zone and the surface affected area. However, the maximum slope and horizontal propagation distance of the fracture zone are larger. 5) the slope 緯 of the site has an important effect on the shear deformation of soil layer and the propagation of fracture zone. With the increase of the surface inclination, the vertical displacement required for the rupture zone out of the surface increases, and the horizontal propagation distance of the fracture zone decreases. No matter the surface inclination 緯 decreases from 0 擄to -5 擄or increases from 0 擄to 5 擄, the maximum slope angle of the steep ridge becomes larger and the width of the affected area becomes larger.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU43

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本文編號：2281524