靠崖式黄土窑洞结构传力机制研究

RESEARCH ON THE FORCE TRANSFER MECHANISM OF LOESS CAVE DWELLING BY CLIFF

以靠崖式窑洞为研究对象,使用ANSYS有限元分析软件对其单孔窑洞的传力机制进行了分析,并考虑了覆土厚度、窑洞跨度、拱矢高以及侧墙高度各参数对窑洞受力性能的影响。同时,还研究了多孔靠崖式窑洞的相互协同作用,分析窑腿宽度对多孔窑洞周围土体应力及位移的影响。结果表明:靠崖式窑洞通过拱券体系将上覆土压力传递给侧墙,窑洞周围土体基本处于受压状态,仅拱券顶部会出现主拉应力,此为窑洞出现窑顶坍塌的诱因。开挖窑洞会造成土体扰动、荷载释放,从而导致窑洞周围土体发生应力和位移变化。通过参数分析,窑洞上覆土厚度、窑洞跨度、拱矢高以及侧墙高度中某单一参数增大均会导致窑洞周围土体位移的增大,但影响程度不一,其中覆土厚度导致的变化最为显著。多孔窑洞的主压应力水平和窑洞横向、窑洞竖向位移均显著大于单孔窑洞。在建造多孔窑洞时,应当合理设置窑腿宽度,确保窑洞结构的稳定性。

The paper took the loess cave dwelling by cliff as the research object,and analyzed the force transfer mechanism of single-hole cave by using finite element analysis software ANSYS. The influence of the thickness of the overlying soil,the span of the cave,the height of the arch and the height of the side wall on the mechanical properties of the cave were considered. Furthermore,the mutual synergy of multihole cave and the effect of the width of the kilnleg on the soil stress and displacement around the cave were analyzed. The results showed that the overlying soil pressure of cave was transferred from the arch system to the side wall,and the soil around the cave was basically in a state of compression. The principal tensile stress appeared only at the top of the arch and caused the collapse of the top of the cave. Excavation of cave would cause soil disturbance and load release,which led to the change of soil stress and displacement around cave. Through parameter analysis,the displacement of the soil around the cave increased with the increase of the thickness of the overburden,the span of the cave,the height of the arch and the height of the side wall. The degrees of influence were different,and the thickness of the overlying soil was the most significant. By comparison,the main pressure stress and the horizontal-direction and vertical-direction displacement of the multihole cave were obviously larger than that of the single-hole cave. Therefore,the width of the kiln-leg should be set up reasonably to ensure the stability of the cave structure in the construction of multihole cave.