铁路隧道不同跨度下水平旋喷桩承载特性分析

为探究水平旋喷桩在不同跨度铁路隧道下承载特性,依托南三龙铁路与赣龙复线联络线道岔进新考塘隧道影响段存在的7种不同隧道跨度断面,采用二维有限元方法,模拟7种不同跨度下水平旋喷桩预支护效果,分析水平旋喷桩结构变形、应力及塑性应变规律。计算结果表明:不同跨度下,旋喷桩变形和常规隧道衬砌变形类似,即拱顶沉降,拱肩、腰、脚等处体现不同程度收敛,各点变形随跨度增大而增长,当跨度大于16 m时,增长速率加快,拱肩及拱腰位置尤其明显;旋喷桩内力部分,当跨度较小时,拱顶内侧受拉,而拱腰处受压,当宽度增大,拱部拉应力区向拱腰处扩展,且拉应力极值增大,而拱腰与拱脚之间压应力迅速增大;随着隧道跨度不断增大,水平旋喷桩等效塑性应变不断增大,影响范围自拱顶到拱脚呈扩大趋势。

Analysis of Bearing Capacity of Horizontal Jet Grouting Piles in Different Span of Railway Tunnels

In order to explore the bearing characteristics of the horizontal jet grouting pile in different span railway tunnels,this paper refers to the three different tunnel span sections of the influence section of the Nanping-Sanming-Longyan Railway and the Ganzhou-Longyan double track turnout into the XinRaotang Tunnel. The two-dimensional finite element method is employed to simulate the effects of horizontal jet grouting piles in 7 different spans,analyze the deformation,stress and plastic strain law of horizontal jet grouting piles. The results show that the deformation of the jet grouting pile is similar to that of the conventional tunnel lining in different spans,that is,the settlement of the arch and different convergences at the shoulder,waist and foot; the deformation at each point increases with the increase of the span; where the span is over 16 m,the deformation rate is accelerated,especially at the arch shoulder and arch waist; in case of small span,the inside vault is subject to tension,while the arch waist is subject to pressure; when the width increases,the compressive stress increases,and the compressive stress between the arch waist and the arch foot is increasing rapidly; with the increasing of tunnel span,the equivalent plastic strain of the horizontal jet grouting pile is increasing and the influence range tends to increase from arch top to arch foot.