采空区上方交通荷载作用下的路基沉降分析

发布时间：2019-04-25 19:13

【摘要】：在矿产资源丰富的地方,越来越多的公路不得不修建在采空区四周或穿越采空区。采空区会影响其上覆岩层的属性,采空区道路在受到自重和外荷载作用会产生大面积的地表变形,进而引起路面开裂,严重时甚至出现大面积坍塌等破坏,影响公路的正常运营同时造成恶劣的社会影响。为保证采空区公路的正常运营,本文以河南某线采空区高速公路的修建和改建工程为背景,考虑交通荷载、采空区与路基相对位置等影响因素,分析采空区上方路基的沉降规律。本文的研究内容和结论如下:(1)对采空区公路沉陷路段进行现场踏勘并钻探取样,结合实验室分析得到岩层的分布情况,运用分层求和法对采空区路基沉降进行理论分析。(2)基于现场勘查来进行软件模拟,针对有无采空区两种状态,研究标准轴载作用下采空区上覆岩体的沉降变化规律。结果表明在动荷载作用周期内,采空区的存在加快了上覆岩体进入塑性变形的时间,而且越靠近采空区的岩层进入塑性变形的时间越短,反之越长。存在采空区时,上覆岩层沉降呈现出由减小到平稳最后再次减小的过程,符合采空区三带划分。(3)改变采空区相对于路基在竖向和横向上的位置,分析不同位置时标准轴载作用下的路基沉降规律。结果表明:当采空区深度在20~60m(路基水平面为0m)变化时,路基的沉降变化较大,60~80m时路基沉降无显著变化;采空区横向位置在-18~10m(道路右坡脚向右为正)时,路基的沉降急剧减小,10~15m时沉降变化缓慢。由此可确定标准荷载作用下采空区路基的临界安全区域。(4)通过交通量调查确定该公路段上作用的重载,研究重载和标准轴载作用下采空区道路的路基沉降变形。结果表明重载作用下的采空区道路路基比标准轴载作用下的路基达到破坏的时间更短,而且产生的不均匀沉降量数值更大。因此对于采空区道路要注意对重载车辆进行限行。(5)选定现场沉陷较大的试验段,埋设沉降观测设备,对现场试验路段进行路基沉降监测,并将其与软件模拟结果对比。结果表明:监测数据与模拟结果变化趋势一致。本文对采空区路基沉降的研究可用于前期采空区道路路线的规划中,对采空区道路运营期间的维修和养护具有重要的参考意义。
[Abstract]:In mineral-rich areas, more and more roads have to be built around or across goaf. Goaf will affect the properties of overlying strata. Under the action of self-weight and external load, the road in goaf will cause large-area surface deformation, and then cause pavement cracking, even large-area collapse and so on. It affects the normal operation of the highway and causes bad social effects at the same time. In order to ensure the normal operation of the goaf highway, this paper takes the construction and reconstruction of the highway in the goaf of Henan province as the background, considering the influence factors such as the traffic load, the relative position of the goaf and the roadbed, and so on. The settlement law of roadbed above goaf is analyzed. The research contents and conclusions of this paper are as follows: (1) on-the-spot exploration and drilling sampling are carried out on the road subsidence section in goaf, and the distribution of rock strata is obtained by combining with laboratory analysis. The method of layer summation is used to analyze the settlement of roadbed in goaf. (2) the software simulation is carried out based on field survey, aiming at the two states of goaf or not, the law of subsidence change of overlying rock mass in goaf under the action of standard axial load is studied. The results show that in the period of dynamic loading, the existence of goaf accelerates the time for overlying rock mass to enter plastic deformation, and the closer it is to goaf, the shorter the time of entering plastic deformation, and vice versa. When there is goaf, the subsidence of overlying strata decreases from decreasing to steady and then decreases again, which accords with the division of three zones in goaf. (3) change the position of goaf relative to roadbed in vertical and lateral direction. The settlement law of roadbed under the action of standard axial load at different positions is analyzed. The results show that when the depth of goaf is 20 m 60 m (the horizontal level of roadbed is 0 m), the settlement of roadbed varies greatly, but the settlement of roadbed does not change significantly when the depth of mined-out area is 60 m. When the lateral position of the goaf is-18 ~ 10 m (the right foot of the road is positive), the settlement of the roadbed decreases sharply, and the settlement changes slowly at the time of 10 ~ 15 m. Thus the critical safe area of mined-out roadbed under standard load can be determined. (4) the heavy load acting on the highway segment can be determined by the investigation of traffic volume, and the settlement and deformation of roadbed in mined-out area under the action of heavy load and standard axial load can be studied. The results show that the failure time of roadbed in mined-out area under heavy load is shorter than that under standard axial load, and the value of non-uniform settlement is larger. Therefore, we should pay attention to traffic restrictions on heavy-duty vehicles in goaf roads. (5) select the test section with large subsidence on the spot, embed settlement observation equipment, monitor the roadbed settlement of the field test section, and compare it with the simulation results of the software. The results show that the trend of monitoring data is consistent with the simulation results. In this paper, the study of roadbed settlement in goaf can be used in the planning of road route in mined-out area, and it has important reference significance for maintenance and maintenance of road in goaf during operation.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.1

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