隧洞结构受力及变形特征的离心模型试验研究

随着地下工程建筑的不断发展 ,对地下结构受力和变形估计的要求由定性走向定量 ,为此 ,结合一拟建大型地下隧洞工程 ,通过离心模型试验 ,研究了砂土中隧洞衬砌的土压力和变形特征以及施工间隙的影响。试验共做了 3个模型 ,分别模拟无间隙以及间隙高度为 10 cm和 2 0 cm的情况。试验结果表明 ,隧洞周围砂土通过发挥拱效应 ,在很小的支护压力下能够保持稳定 ,临界支护压力不仅远小于原位土压力 ,也远小于 Terzaghi松动土压力

Centrifuge model test study of the earth pressure and deformation of tunnel lining

Along with the developments of underground engineering and construction technology, the pressures acting on structures and the deformations of structures are required to be estimated more quantitatively, and some key problems, such as the influence of soil arching action on earth pressure, however, are still needed to be realized more accurately. By centrifuge model tests, the influence of arching effect of sand on earth pressure and the deformation characteristics of tunnel lining were investigated. Three model tests were conducted; initial clearances of 0, 10 and 20 cm between tunnel lining and excavated surface were modeled. Earth pressures and the strains of lining were measured. The results of experiments reveal strong arching effect of sand, which greatly decrease the earth pressures acting on tunnel and the internal force of lining and sand mass around tunnel can maintain stable with supporting pressure much smaller than the loosening pressure calculated by Terzaghi's formulation.