本文選題：飽和半空間 + 襯砌隧道�。� 參考：《天津城建大學(xué)》2015年碩士論文

【摘要】：當(dāng)今中國經(jīng)濟(jì)蓬勃發(fā)展,城市交通運(yùn)輸網(wǎng)絡(luò)立體化不斷完善。地鐵已然成為了人們賴以出行的交通工具。因此,研究飽和土體中襯砌隧道對(duì)平面P、SV波的散射以及襯砌隧道在內(nèi)部爆炸荷載作用下的瞬態(tài)反應(yīng)對(duì)工程抗震、抗爆以及防災(zāi)減災(zāi)具有非常重要的理論和現(xiàn)實(shí)意義。(一)基于Biot兩相介質(zhì)理論,本文首先采用一種高精度的間接邊界積分方程法研究了飽和半空間中襯砌隧道對(duì)彈性波(P1波和SV波)的散射問題,并給出了不同參數(shù)下地表位移幅值、襯砌動(dòng)應(yīng)力集中因子及表面孔隙水壓分布圖和相應(yīng)的頻譜結(jié)果。數(shù)值分析表明:飽和半空間襯砌隧道對(duì)P、SV波的散射特征取決于圍巖介質(zhì)孔隙率、入射波的頻率和角度、隧道埋深等因素;隧道外壁透水狀態(tài)對(duì)地表位移和隧道應(yīng)力影響不大;隧道上方地表位移幅值放大程度隨孔隙率增大逐漸減小;隨著入射頻率的增加動(dòng)應(yīng)力分布更加復(fù)雜,出現(xiàn)多個(gè)峰值區(qū)域;對(duì)傾斜入射情況,隧道應(yīng)力集中更為明顯;隨埋深增大,地表位移幅值和襯砌表面動(dòng)應(yīng)力譜振蕩更為劇烈,但幅值會(huì)有所降低。另外,按波速比等效的單相介質(zhì)模型可以近似計(jì)算平面波入射下隧道-飽和圍巖的位移場和應(yīng)力場。(二)本文研究飽和半空間中彈性襯砌在內(nèi)部爆炸荷載作用下的瞬態(tài)動(dòng)力反應(yīng)。通過算例給出了爆炸荷載作用下地表位移、襯砌動(dòng)應(yīng)力、圍巖徑向位移和孔壓的時(shí)程響應(yīng)結(jié)果,并對(duì)比分析了飽和半空間和全空間場地時(shí)程響應(yīng)的區(qū)別。研究表明:透水和不透水條件對(duì)爆炸荷載的時(shí)程響應(yīng)影響很小;隨著孔隙率的增加,飽和場地受到的爆炸影響減小,襯砌受到的爆炸影響增大;隨襯砌埋深的增加地表位移峰值減小,即覆土層越厚則地表受到的爆炸影響越小;爆炸荷載作用初期全空間襯砌和半空間襯砌的爆炸時(shí)程響應(yīng)均相同,之后埋深較小的襯砌中上部點(diǎn)位明顯受到地表反射波動(dòng)的影響,使得動(dòng)應(yīng)力幅值、圍巖徑向位移相比全空間曲線出現(xiàn)大幅度增加。
[Abstract]:Nowadays, the economy of China is booming, and the urban transportation network is becoming more and more perfect.The subway has become the vehicle on which people travel.Therefore, it is of great theoretical and practical significance to study the scattering of plane PNSV wave from lining tunnel in saturated soil and the transient response of lining tunnel under the action of internal explosion load for engineering aseismic, anti-explosion and disaster prevention and mitigation.(1) based on the Biot two-phase medium theory, a high-precision indirect boundary integral equation method is used to study the scattering of elastic waves P1 and SV waves by lining tunnels in saturated half-space.The surface displacement amplitude, lining dynamic stress concentration factor, surface pore water pressure distribution and corresponding spectrum results are also given.Numerical analysis shows that the scattering characteristics of saturated half-space lining tunnel to PNSV wave depend on the porosity of surrounding rock, the frequency and angle of incident wave, the depth of tunnel, and so on, and the permeable state of tunnel outer wall has little effect on surface displacement and tunnel stress.The amplitudes of surface displacement over the tunnel gradually decrease with the increase of porosity, the distribution of dynamic stress is more complex with the increase of incident frequency, and there are many peak regions, and the stress concentration of tunnel is more obvious in the case of inclined incidence.With the increase of buried depth, the amplitude of surface displacement and the dynamic stress spectrum oscillation of lining surface are more intense, but the amplitude will decrease.In addition, the displacement field and stress field of tunnel-saturated surrounding rock under plane wave incidence can be approximately calculated by the equivalent single-phase medium model with wave velocity ratio.(2) in this paper, the transient dynamic response of elastic lining under internal explosive load in saturated half-space is studied.The results of time-history response of ground displacement, dynamic stress of lining, radial displacement of surrounding rock and pore pressure under explosive loading are given. The difference between saturated half-space and full-space site is analyzed.The results show that the influence of permeability and impermeability on the time history response of explosive load is very small, and with the increase of porosity, the effect of explosion on saturated site is reduced, and that on lining is increased.The peak value of surface displacement decreases with the increase of lining depth, that is, the thicker the overburden layer is, the smaller the explosion effect is, and the explosion time history response of the full space lining and half space lining are the same at the initial stage of explosive loading.The lower buried depth of the middle and upper part of the lining is obviously affected by the surface reflection fluctuation, which makes the amplitude of dynamic stress and the radial displacement of surrounding rock increase significantly compared with the whole space curve.
【學(xué)位授予單位】：天津城建大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U451.4

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本文編號(hào)：1766306