路基支擋結(jié)構(gòu)地震動力響應及抗震設(shè)計改進技術(shù)研究
發(fā)布時間：2018-07-14 13:40
【摘要】：近年來發(fā)生在我國的幾次大地震造成了震區(qū)路基支擋工程的大量破壞,引發(fā)了人們對生命線工程的嚴重擔憂。路基支擋工程在地震作用下的破壞模式、震后修復措施及其抗震技術(shù),已成為當前研究的熱點和難點問題。本文利用汶川地震路基支擋結(jié)構(gòu)的實震資料,通過采用大型振動臺模型試驗、數(shù)值模擬以及解析計算,研究了地震作用下柔性擋墻和剛性擋墻的動力響應特性和變形破壞機制,以及錨固邊坡的地震穩(wěn)定性影響因素等,并針對加筋土擋墻和格賓擋墻提出了抗震設(shè)計改進方法和措施。本文的主要工作及研究結(jié)論如下：(1)傾覆破壞是路肩墻在地震作用下的主要破壞模式,提高路肩墻抗傾覆穩(wěn)定性應是其抗震設(shè)計的核心；路塹墻被毀雖會造成道路被掩埋,但經(jīng)清理后即可恢復通車,總體上看其震害較輕。擋墻的震害受多種因素的影響,擋墻的砌筑方法是影響其震害程度的主要內(nèi)在因素,地震烈度則是影響擋墻震害程度的主要外部因素,另外,道路線形和斷裂帶走向也有重要影響。應用地質(zhì)雷達對震后擋墻進行檢測,操作簡便檢測效率高,且對線路運營不造成任何影響,通過連續(xù)的雷達圖像可快速準確地判斷擋墻的震損狀況。(2)利用汶川地震豐富的近場實震資料,分析總結(jié)了地震作用下?lián)鯄Φ淖冃纹茐哪Ｊ?指出地基類型對擋墻的變形模式有著直接的影響。傾斜變形和推移變形分別是巖質(zhì)地基擋墻和土質(zhì)地基擋墻最主要的變形模式。基于Winkler地基模型,認為土體是一系列彈簧和理想剛塑性體的組合體,分析得到了不同變形模式下?lián)鯄Φ卣鹬鲃油翂毫Φ姆植家?guī)律。結(jié)果表明：擋墻的地震土壓力分布特征與變形模式密切相關(guān),除了平行推移模式,其余變形模式下?lián)鯄Φ卣鹜翂毫ρ貕Ω叨汲史蔷�性分布；巖質(zhì)地基擋墻的地震土壓力合力作用點要比土質(zhì)地基擋墻高。通過開展位于巖質(zhì)地基和土質(zhì)地基上擋墻的振動臺模型試驗,對文中提出的擋墻地震土壓力計算方法進行了驗證,發(fā)現(xiàn)試驗結(jié)果和理論分析結(jié)果較相吻合(3)為研究填料性質(zhì)對擋墻地震動力特性的影響,開展了不同填料的擋墻振動臺試驗,結(jié)果發(fā)現(xiàn)填料性質(zhì)對擋墻的動力特性及變形破壞機制影響顯著。由于碎石土容易壓實,地震波動力作用可較為直接地作用于墻背,故地震土壓力要比石英砂擋墻以及風化花崗巖擋墻都大；地震土壓力合力作用點也與填料性質(zhì)密切相關(guān),碎石土填料擋墻的合力作用點高于0.33倍墻高,且隨著PGA的增加,合力作用點高度也隨之升高；在地震土壓力和作用點高度的綜合影響下,碎石土擋墻的抗傾覆安全系數(shù)小于風化花崗巖和石英砂擋墻,汶川震區(qū)擋墻多傾覆破壞,驗證了上述結(jié)論。采用數(shù)值模擬對試驗結(jié)果進行了驗證,認為碎石土填料擋墻的動位移較另外兩種填料的擋墻都小。(4)為分析比較條帶式和包裹式加筋土擋墻的地震動力響應特征,開展了以上兩種加筋土擋墻模型的大型振動臺試驗。結(jié)合震害調(diào)查的結(jié)果,發(fā)現(xiàn)砌塊式加筋土擋墻在地震作用下的破壞模式主要表現(xiàn)為局部砌塊的松動變形,很少會出現(xiàn)整體垮塌的情況。相比條帶式加筋土擋墻,包裹式加筋土擋墻在地震作用下產(chǎn)生的變形量要小。在相同地震動量級作用下,包裹式加筋土擋墻相應部位的水平加速度放大系數(shù)要小于條帶式加筋土擋墻,但峰值動土壓力卻要比條帶式加筋土擋墻大,這是因為包裹式加筋土擋墻面板在地震作用下的變形量小,對土體的約束能力強所致。因此,在抗震設(shè)防區(qū),特別是在高地震烈度區(qū)進行加筋土擋墻的選型時,包裹式加筋土擋墻應作為一種優(yōu)選結(jié)構(gòu)。分析認為加筋土擋墻在進行抗震設(shè)計時除了要進行穩(wěn)定性的檢算外,還應檢算墻體的變形量,加筋土擋墻在地震作用下的最大變形量應小于允許的變形量。為維持線路的正常使用,加筋土擋墻的變形指數(shù)應控制在4%以內(nèi)。若驗算得到的變形量超出允許值,可采取增大墻后填土的壓實度和適當增加拉筋長度,以及加厚墻體和降低墻體坡率等措施。(5)為研究柔性擋墻的地震動力響應特性及變形特征,開展了格賓加筋擋墻與生態(tài)加筋擋墻的大型振動臺模型試驗。結(jié)果表明：在地震作用下,兩種柔性擋墻的峰值動土壓力沿墻高呈現(xiàn)中間小兩端大的分布特征。鼓脹變形是地震作用下兩種擋墻的主要變形模式,變形后擋墻的地震土壓力將會有一定程度的衰減。對于鐵路及高等級公路柔性擋墻的抗震設(shè)計,除要保證其整體穩(wěn)定性外,還需控制墻體的局部變形量,采用易壓實的填料或增加墻體材料的彈性模量和厚度均可以有效控制擋墻的地震變形量。施加受力撐可有效減小格賓網(wǎng)箱的變形,尤其是施加交叉斜撐后變形量的減小最為顯著,因此,建議對于變形控制異常嚴格的高等級道路,可采用該方法來控制格賓擋墻的變形量。(6)現(xiàn)場調(diào)研發(fā)現(xiàn),對于錨固工程,錨索的抗震能力最為突出,其次為錨桿,并且認為決定錨桿(錨索)抗震效果的主要因素為錨固長度。掛網(wǎng)噴射混凝土具有一定的抗震能力,而主動網(wǎng)則幾乎不具備抗震能力。通過采用擬靜力法對汶川震區(qū)內(nèi)錨桿支護邊坡的地震穩(wěn)定性進行驗算后得知,邊坡的動力安全系數(shù)隨錨桿長度的增加而增大。利用數(shù)值方法分析了地震作用下錨桿支護邊坡的動力響應特征以及錨固參數(shù)的影響規(guī)律。結(jié)果表明,錨固措施對邊坡的PGA放大系數(shù)有明顯的抑制作用,地震作用下錨固邊坡邊坡最大水平位移出現(xiàn)在坡頂,錨桿的軸力也要比靜力工況下大;坡面PGA放大系數(shù)和最大位移隨錨桿長度的增大而減小,隨錨桿間距的減小而增大,錨桿傾角對邊坡PGA放大系數(shù)的影響規(guī)律并不明顯。
[Abstract]:Several major earthquakes in China in recent years have caused a lot of damage to the subgrade support project in the earthquake area, causing serious concern for the lifeline engineering. The failure mode of the subgrade retaining engineering under the earthquake action, the post earthquake repair measures and the seismic technology have become the hot and difficult problems in the research. This paper uses the Wenchuan earthquake. By using large vibration table model test, numerical simulation and analytical calculation, the dynamic response characteristics and deformation mechanism of flexible retaining wall and rigid retaining wall under earthquake action, as well as the influence factors of the seismic stability of anchored slope are studied by using large vibration table model test, numerical simulation and analytical calculation, and the reinforced earth retaining wall and the guest retaining wall are put forward. The main work and conclusions of this paper are as follows: (1) the overturning failure is the main failure mode of the shoulder wall under the earthquake action, and the improvement of the anti overturning stability of the shoulder wall should be the core of its seismic design; the destruction of the cutting wall will cause the road to be buried, but it can be restored to traffic after cleaning, overall. The seismic damage of the retaining wall is affected by many factors. The masonry method of the retaining wall is the main internal factor affecting the magnitude of the earthquake damage, and the seismic intensity is the main external factor affecting the degree of the damage to the retaining wall. In addition, the road alignment and the strike of the fault zone also have important influence. It has high efficiency and no effect on line operation, and can quickly and accurately judge the earthquake damage condition of the retaining wall through continuous radar images. (2) the deformation and failure modes of the retaining wall under earthquake action are analyzed and summarized by using the abundant near field earthquake data of Wenchuan earthquake, and it is pointed out that the type of foundation is direct to the deformation mode of the retaining wall. The slope deformation and the bed load deformation are the most important deformation modes of the rock foundation retaining wall and the soil foundation retaining wall respectively. Based on the Winkler foundation model, the soil is considered as a combination of a series of springs and ideal rigid plastic bodies. The distribution of the active earth pressure on the retaining wall under different deformation modes is analyzed. The results show that the retaining wall is the retaining wall. The distribution characteristics of seismic soil pressure are closely related to the deformation model. In addition to the parallel model, the seismic soil pressure of the retaining wall is nonlinear along the wall, and the seismic soil pressure in the rock foundation wall is higher than that of the soil foundation retaining wall. The dynamic platform model test is used to verify the seismic soil pressure calculation method proposed in this paper. It is found that the experimental results are in good agreement with the theoretical analysis results (3) to study the influence of the properties of the filler on the dynamic characteristics of the retaining wall, and the vibration table test of the retaining wall with different fillers is carried out. The results of the dynamic characteristics and changes of the filler properties to the retaining wall are found. The effect of seismic wave dynamic action on the back of the wall is more directly than that of the quartz sand retaining wall and the weathered granite retaining wall. The resultant force of the seismic soil pressure is closely related to the properties of the filler, and the resultant force of the gravel packing retaining wall is more than 0.33 times. The wall height is high, and with the increase of PGA, the point height of the resultant force increases. Under the comprehensive influence of the seismic soil pressure and the height of the action point, the anti overturning safety factor of the gravel soil retaining wall is less than the weathered granite and the quartz sand retaining wall, and the retaining wall in the Wenchuan seismic area is overturned and destroyed. It is proved that the dynamic displacement of the gravel packing retaining wall is smaller than that of the other two kinds of fillers. (4) in order to analyze and compare the seismic dynamic response characteristics of the strip type and the wrapped reinforced earth retaining wall, the large shaking table test of the above two reinforced earth retaining wall models is carried out. The failure mode of the earthquake is mainly manifested in the loosening and deformation of the local block, and the overall collapse is seldom seen. Compared with the strip reinforced earth retaining wall, the deformation of the wrapped reinforced earth retaining wall is smaller under the earthquake action. The horizontal acceleration magnification of the corresponding part of the wrapped reinforced earth retaining wall under the action of the same ground motion The coefficient is less than the strip reinforced earth retaining wall, but the peak dynamic earth pressure is larger than the strip reinforced earth retaining wall. This is due to the small deformation of the reinforced earth retaining wall panel under the earthquake action and the strong restraint to the soil. The wrapped reinforced earth retaining wall should be used as a preferred structure. It is considered that the deformation of the wall should be calculated in addition to the calculation of stability when the reinforced earth retaining wall is designed for seismic design. The maximum deformation of the reinforced earth retaining wall under the earthquake action should be less than that of the allowed deformation. The deformation index should be controlled within 4%. If the calculated deformation amount exceeds the allowable value, the compaction degree of the backfill and the length of the reinforced bar, the thickening wall and the reduction of the wall slope can be taken. (5) to study the seismic dynamic response characteristics and the deformation characteristics of the flexible retaining wall, the green reinforcement retaining wall and the ecological addition are carried out. The large shaking table test of the reinforced retaining wall shows that the peak dynamic pressure of the two kinds of flexible retaining walls is characterized by the large middle and small two ends along the wall under the earthquake action. The bulging deformation is the main deformation mode of the two kinds of retaining walls under the earthquake action, and the seismic soil pressure of the retaining wall will be attenuated to a certain extent after the deformation. The seismic design of the flexible retaining wall of road and high grade highway, in addition to ensuring its overall stability, also needs to control the local deformation of the wall, and the elastic modulus and thickness of the wall material can effectively control the deformation of the retaining wall, and the deformation of the bin can be effectively reduced by exerting force support, especially in the application. It is suggested that this method can be used to control the deformation of the bin retaining wall. (6) it is found that the seismic capacity of the anchorage cable is the most prominent, the next is the anchor, and the aseismic effect of the anchor (Anchorage) is decided. The main factor is the anchorage length. The shotcrete has a certain seismic capacity, while the active network has almost no seismic capacity. By using the pseudo static method, the seismic stability of the bolting slope in Wenchuan earthquake area is checked, and the dynamic safety factor of the slope is increased with the increase of the anchor length. The dynamic response characteristics of the anchorage slope under the earthquake action and the influence of anchorage parameters are analyzed. The results show that the anchorage measures have obvious restraining effect on the PGA amplification factor of the slope. The maximum horizontal displacement of the slope of the anchorage slope appears on the top of the slope under the earthquake action, and the axial force of the anchor rod is also larger than that under the static condition; the slope surface is placed on the slope of PGA. The large coefficient and maximum displacement decrease with the increase of anchor length, and increase with the decrease of anchor spacing. The influence of anchor angle on the PGA magnification coefficient of slope is not obvious.
【學位授予單位】：西南交通大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：U416.1
本文編號：2121826
[Abstract]:Several major earthquakes in China in recent years have caused a lot of damage to the subgrade support project in the earthquake area, causing serious concern for the lifeline engineering. The failure mode of the subgrade retaining engineering under the earthquake action, the post earthquake repair measures and the seismic technology have become the hot and difficult problems in the research. This paper uses the Wenchuan earthquake. By using large vibration table model test, numerical simulation and analytical calculation, the dynamic response characteristics and deformation mechanism of flexible retaining wall and rigid retaining wall under earthquake action, as well as the influence factors of the seismic stability of anchored slope are studied by using large vibration table model test, numerical simulation and analytical calculation, and the reinforced earth retaining wall and the guest retaining wall are put forward. The main work and conclusions of this paper are as follows: (1) the overturning failure is the main failure mode of the shoulder wall under the earthquake action, and the improvement of the anti overturning stability of the shoulder wall should be the core of its seismic design; the destruction of the cutting wall will cause the road to be buried, but it can be restored to traffic after cleaning, overall. The seismic damage of the retaining wall is affected by many factors. The masonry method of the retaining wall is the main internal factor affecting the magnitude of the earthquake damage, and the seismic intensity is the main external factor affecting the degree of the damage to the retaining wall. In addition, the road alignment and the strike of the fault zone also have important influence. It has high efficiency and no effect on line operation, and can quickly and accurately judge the earthquake damage condition of the retaining wall through continuous radar images. (2) the deformation and failure modes of the retaining wall under earthquake action are analyzed and summarized by using the abundant near field earthquake data of Wenchuan earthquake, and it is pointed out that the type of foundation is direct to the deformation mode of the retaining wall. The slope deformation and the bed load deformation are the most important deformation modes of the rock foundation retaining wall and the soil foundation retaining wall respectively. Based on the Winkler foundation model, the soil is considered as a combination of a series of springs and ideal rigid plastic bodies. The distribution of the active earth pressure on the retaining wall under different deformation modes is analyzed. The results show that the retaining wall is the retaining wall. The distribution characteristics of seismic soil pressure are closely related to the deformation model. In addition to the parallel model, the seismic soil pressure of the retaining wall is nonlinear along the wall, and the seismic soil pressure in the rock foundation wall is higher than that of the soil foundation retaining wall. The dynamic platform model test is used to verify the seismic soil pressure calculation method proposed in this paper. It is found that the experimental results are in good agreement with the theoretical analysis results (3) to study the influence of the properties of the filler on the dynamic characteristics of the retaining wall, and the vibration table test of the retaining wall with different fillers is carried out. The results of the dynamic characteristics and changes of the filler properties to the retaining wall are found. The effect of seismic wave dynamic action on the back of the wall is more directly than that of the quartz sand retaining wall and the weathered granite retaining wall. The resultant force of the seismic soil pressure is closely related to the properties of the filler, and the resultant force of the gravel packing retaining wall is more than 0.33 times. The wall height is high, and with the increase of PGA, the point height of the resultant force increases. Under the comprehensive influence of the seismic soil pressure and the height of the action point, the anti overturning safety factor of the gravel soil retaining wall is less than the weathered granite and the quartz sand retaining wall, and the retaining wall in the Wenchuan seismic area is overturned and destroyed. It is proved that the dynamic displacement of the gravel packing retaining wall is smaller than that of the other two kinds of fillers. (4) in order to analyze and compare the seismic dynamic response characteristics of the strip type and the wrapped reinforced earth retaining wall, the large shaking table test of the above two reinforced earth retaining wall models is carried out. The failure mode of the earthquake is mainly manifested in the loosening and deformation of the local block, and the overall collapse is seldom seen. Compared with the strip reinforced earth retaining wall, the deformation of the wrapped reinforced earth retaining wall is smaller under the earthquake action. The horizontal acceleration magnification of the corresponding part of the wrapped reinforced earth retaining wall under the action of the same ground motion The coefficient is less than the strip reinforced earth retaining wall, but the peak dynamic earth pressure is larger than the strip reinforced earth retaining wall. This is due to the small deformation of the reinforced earth retaining wall panel under the earthquake action and the strong restraint to the soil. The wrapped reinforced earth retaining wall should be used as a preferred structure. It is considered that the deformation of the wall should be calculated in addition to the calculation of stability when the reinforced earth retaining wall is designed for seismic design. The maximum deformation of the reinforced earth retaining wall under the earthquake action should be less than that of the allowed deformation. The deformation index should be controlled within 4%. If the calculated deformation amount exceeds the allowable value, the compaction degree of the backfill and the length of the reinforced bar, the thickening wall and the reduction of the wall slope can be taken. (5) to study the seismic dynamic response characteristics and the deformation characteristics of the flexible retaining wall, the green reinforcement retaining wall and the ecological addition are carried out. The large shaking table test of the reinforced retaining wall shows that the peak dynamic pressure of the two kinds of flexible retaining walls is characterized by the large middle and small two ends along the wall under the earthquake action. The bulging deformation is the main deformation mode of the two kinds of retaining walls under the earthquake action, and the seismic soil pressure of the retaining wall will be attenuated to a certain extent after the deformation. The seismic design of the flexible retaining wall of road and high grade highway, in addition to ensuring its overall stability, also needs to control the local deformation of the wall, and the elastic modulus and thickness of the wall material can effectively control the deformation of the retaining wall, and the deformation of the bin can be effectively reduced by exerting force support, especially in the application. It is suggested that this method can be used to control the deformation of the bin retaining wall. (6) it is found that the seismic capacity of the anchorage cable is the most prominent, the next is the anchor, and the aseismic effect of the anchor (Anchorage) is decided. The main factor is the anchorage length. The shotcrete has a certain seismic capacity, while the active network has almost no seismic capacity. By using the pseudo static method, the seismic stability of the bolting slope in Wenchuan earthquake area is checked, and the dynamic safety factor of the slope is increased with the increase of the anchor length. The dynamic response characteristics of the anchorage slope under the earthquake action and the influence of anchorage parameters are analyzed. The results show that the anchorage measures have obvious restraining effect on the PGA amplification factor of the slope. The maximum horizontal displacement of the slope of the anchorage slope appears on the top of the slope under the earthquake action, and the axial force of the anchor rod is also larger than that under the static condition; the slope surface is placed on the slope of PGA. The large coefficient and maximum displacement decrease with the increase of anchor length, and increase with the decrease of anchor spacing. The influence of anchor angle on the PGA magnification coefficient of slope is not obvious.
【學位授予單位】：西南交通大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：U416.1
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