本文選題：隧道工程 + 初始地應力場　； 參考：《中國公路學報》2017年10期

【摘要】：為探明藍家?guī)r超大埋深特長公路隧道軸線方向的初始地應力場狀態(tài),依據(jù)工程地質勘察報告,利用有限元計算軟件ANSYS建立了工程區(qū)三維地質模型;以現(xiàn)場水壓致裂法測得的初始地應力資料為研究基礎,通過地質力學分析確定影響初始地應力場形成的主要因素,并將其表達為數(shù)值計算所需的邊界和初始條件;在各影響因素單獨作用下,計算得到水壓致裂法各測點位置的地應力量值;運用多元回歸分析獲得了藍家?guī)r隧道軸線方向上的初始地應力場分布規(guī)律。根據(jù)藍家?guī)r隧道軸線處地應力場回歸方程,計算得到現(xiàn)場應力解除法各測點位置處的地應力,并與實測結果進行比較,從而驗證反演回歸計算結果的合理性。結果表明:主應力量值隨埋深呈現(xiàn)出近似線性增長的關系,垂直主應力等于或略大于單位面積上覆巖層的自重應力;主應力量值呈現(xiàn)出S_H(最大水平主應力)S_h(最小水平主應力S_V(垂直主應力)的規(guī)律,表明藍家?guī)r隧道初始地應力場以水平構造應力為主導;主應力量值大部分在20 MPa以上,說明藍家?guī)r隧道為高地應力場隧道;最大水平主應力與最小水平主應力的量值相差較大,根據(jù)摩爾-庫侖強度理論可知隧道水平面內存在較大剪應力,易導致圍巖產生過大變形或破壞;在斷層經過區(qū)域,受斷層擠壓剪切作用,地應力變化劇烈,相對斷層前后的地層而言有一定的應力松弛。
[Abstract]:In order to investigate the initial in-situ stress field in the direction of the axis of the super-large buried ultra-long highway tunnel in Lanjiayan, a three-dimensional geological model of the engineering area was established by using the finite element calculation software ANSYS, according to the engineering geological survey report. Based on the initial in-situ stress data measured by the in-situ hydraulic fracturing method, the main factors affecting the formation of the initial in-situ stress field are determined by geomechanical analysis, and expressed as the boundary and initial conditions required for numerical calculation. Under the influence of each factor alone, the in-situ stress values of the sites measured by hydraulic fracturing method are calculated, and the distribution law of initial geostress field in the axis direction of Lanjiayan tunnel is obtained by multivariate regression analysis. According to the regression equation of in-situ stress field at the axis of Lanjiayan tunnel, the in-situ stress at each measuring point of the in-situ stress relief method is calculated and compared with the measured result, which verifies the rationality of the inverse regression calculation result. The results show that the principal stress value increases linearly with the buried depth, and the vertical principal stress is equal to or slightly greater than the gravity stress of the overlying strata per unit area. The principal stress value shows the rule of Sch (minimum horizontal principal stress) Sv (vertical principal stress), which indicates that the initial geostress field of Lanjiayan tunnel is dominated by horizontal tectonic stress, and the principal stress value is above 20 MPa. It shows that Lanjiayan tunnel is a tunnel with high ground stress field, and the maximum horizontal principal stress and the minimum horizontal principal stress differ greatly. According to the Mohr Coulomb strength theory, there are large shear stresses in the horizontal plane of the tunnel. It is easy to cause excessive deformation or failure of surrounding rock, and in the area of fault passing through, the ground stress changes sharply by the action of compression and shearing of fault, and there is certain stress relaxation relative to the strata before and after the fault.
【作者單位】： 西南交通大學交通隧道工程教育部重點實驗室;西南交通大學土木工程學院;
【基金】：國家重點研發(fā)計劃項目(2016YFC0802201,2016YFC0802202)
【分類號】：U452.11

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