岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
4期
926-932,942
,共8页
模型试验%桩基荷载%隧道开挖模拟%数值分析%地层压力%地层沉降%隧道支护内力
模型試驗%樁基荷載%隧道開挖模擬%數值分析%地層壓力%地層沉降%隧道支護內力
모형시험%장기하재%수도개알모의%수치분석%지층압력%지층침강%수도지호내력
model test%pile foundation load%modeling of tunnel excavation%numerical simulation%soil pressure%ground settlement%internal force of tunnel support
建立了包括地层模型、桩基荷载模型、浅埋隧道开挖模型和支护模型以及桩基荷载、地层压力、地层沉降、支护应变量测装置的平面应变模型试验系统；通过模型试验，研究了不同水平、竖向相对位置处的既有桩基荷载对附近浅埋隧道开挖引起的地层压力重分布、地层沉降及隧道支护内力的影响特征。另外，采用FLAC3D软件，对模型试验及不同工况进行了数值模拟。结果表明：（1）与没有桩基荷载的自由地层中的隧道开挖试验相比较，地层中的既有桩基荷载会明显地改变邻近浅埋隧道开挖引起的地层压力重分布、地层沉降及隧道支护内力；（2）对于桩径和水平相对距离都相同，但桩长不同的桩基荷载，桩长与隧道埋深比值为1.0时，对隧道开挖效应影响最大，二者比值小于1.0时，其影响程度随着比值的减小而减小，二者比值大于1.0时，桩长的改变对隧道开挖效应影响较小；（3）对于桩径和桩长都相同的桩基荷载，对地层压力、地层沉降及支护内力的影响随桩基荷载与隧道的水平距离的减小而增大，桩基荷载距隧道的水平距离与隧道直径比值介于0.5～4.0时，桩基荷载对隧道开挖效应影响较大，隧道较危险，比值介于4.0～6.0时，影响较小，比值＞6.0时，影响可以忽略不计。
建立瞭包括地層模型、樁基荷載模型、淺埋隧道開挖模型和支護模型以及樁基荷載、地層壓力、地層沉降、支護應變量測裝置的平麵應變模型試驗繫統；通過模型試驗，研究瞭不同水平、豎嚮相對位置處的既有樁基荷載對附近淺埋隧道開挖引起的地層壓力重分佈、地層沉降及隧道支護內力的影響特徵。另外，採用FLAC3D軟件，對模型試驗及不同工況進行瞭數值模擬。結果錶明：（1）與沒有樁基荷載的自由地層中的隧道開挖試驗相比較，地層中的既有樁基荷載會明顯地改變鄰近淺埋隧道開挖引起的地層壓力重分佈、地層沉降及隧道支護內力；（2）對于樁徑和水平相對距離都相同，但樁長不同的樁基荷載，樁長與隧道埋深比值為1.0時，對隧道開挖效應影響最大，二者比值小于1.0時，其影響程度隨著比值的減小而減小，二者比值大于1.0時，樁長的改變對隧道開挖效應影響較小；（3）對于樁徑和樁長都相同的樁基荷載，對地層壓力、地層沉降及支護內力的影響隨樁基荷載與隧道的水平距離的減小而增大，樁基荷載距隧道的水平距離與隧道直徑比值介于0.5～4.0時，樁基荷載對隧道開挖效應影響較大，隧道較危險，比值介于4.0～6.0時，影響較小，比值＞6.0時，影響可以忽略不計。
건립료포괄지층모형、장기하재모형、천매수도개알모형화지호모형이급장기하재、지층압력、지층침강、지호응변량측장치적평면응변모형시험계통；통과모형시험，연구료불동수평、수향상대위치처적기유장기하재대부근천매수도개알인기적지층압력중분포、지층침강급수도지호내력적영향특정。령외，채용FLAC3D연건，대모형시험급불동공황진행료수치모의。결과표명：（1）여몰유장기하재적자유지층중적수도개알시험상비교，지층중적기유장기하재회명현지개변린근천매수도개알인기적지층압력중분포、지층침강급수도지호내력；（2）대우장경화수평상대거리도상동，단장장불동적장기하재，장장여수도매심비치위1.0시，대수도개알효응영향최대，이자비치소우1.0시，기영향정도수착비치적감소이감소，이자비치대우1.0시，장장적개변대수도개알효응영향교소；（3）대우장경화장장도상동적장기하재，대지층압력、지층침강급지호내력적영향수장기하재여수도적수평거리적감소이증대，장기하재거수도적수평거리여수도직경비치개우0.5～4.0시，장기하재대수도개알효응영향교대，수도교위험，비치개우4.0～6.0시，영향교소，비치＞6.0시，영향가이홀략불계。
An layered earth model, a pile foundation load model, a shallow tunnel excavation model and an associated support model, together with plane strain model test system for measuring pile foundation load, soil pressure, soil settlement, and support strain are set up. Experiments are conducted to study the influences on soil pressure redistributions, soil set, tunnel crown settlements, and internal forces of the tunnel support caused by a nearby shallow tunnel excavation under the condition of various horizontal and vertical existing pile foundation loads. Moreover, the test process and different working conditions are simulated via the FLAC3D software. The results are as follows:(1) Compared to the tunnel excavation without pre-existing pile foundation loads, pre-existing pile foundation loads can significantly alter the soil pressure redistributions, soil settlements and internal forces of the tunnel support;(2) For pile foundation loads of different length, fixed pile diameter and horizontal position, when the ratio of pile length and tunnel depth is equal to 1.0, it causes a largest influence on the effect of tunnel excavation, in the case of the ratio less than 1.0, the influence decreases with the decrease of the ratio;when the ratio is beyond 1.0, the influence of the pile length change on tunnel excavation effect becomes smaller. (3) For file foundation loads of fixed pile diameter and length, the soil pressure, ground settlement and internal force of tunnel support increase with the decrease of the relative horizontal distance between the pile foundation loads and the tunnel. If the ratio of horizontal distance between the pile foundation loads and the tunnel and tunnel diameter is from 0.5 to 4.0, the tunnel will be in the danger. If the ratio of that is from 4.0 to 6.0, the influence on tunnel caused by the pile foundation loads will become lighter. If the ratio of that is beyond 6.0, the influence can be neglected.
