非极限位移模式下锚拉式挡土墙土压力计算方法研究

发布时间：2018-05-29 03:56

本文选题：锚拉式挡土墙 + 土压力　；参考：《山东大学》2017年硕士论文

【摘要】：挡土墙墙背侧向土压力的大小和分布与土和挡土墙之间的相互作用密切相关,挡土墙的位移模式、位移大小对土压力的大小和分布规律产生重要影响,现有锚拉式挡土墙计算土压力主要采用只能采用用于计算极限状态库伦土压力或郎肯土压力理论进行计算,而锚拉式挡土墙由于受到预应力锚杆的侧向约束作用,墙体侧向变形及位移受到限制,墙后填土尚未达到极限状态,其计算条件与极限状态差异较大。因此本文采用模型试验的方法,结合数值计算方法,在已有研究理论的基础上提出了非极限位移模式下锚拉式挡土墙土压力计算方法。得出主要结论如下:1、悬臂式挡土墙,在上覆荷载作用下,墙体呈现T模式外倾位移,墙背侧向土压力呈峰值在墙体中部的抛物线型分布,土压力为1.5倍静止土压力;在侧向位移作用下墙体呈现RBT模式位移,墙背侧向土压力呈非线性分布,符合刚性挡土墙土压力分布规律,土压力计算推荐采用卢坤林计算方法。2、无预应力锚拉式挡土墙,在上覆荷载作用下,墙体呈现T模式外倾位移,墙背侧向土压力呈峰值在锚杆位置处的抛物线分布,推荐锚杆设置高度为0.5H(H为墙高),土压力为0.8倍静止土压力;在主动侧向位移作用下,墙体呈RB模式外倾位移,墙背侧向土压力亦呈非线性分布,锚杆可显著限制墙体侧向位移,计算方法亦推荐采用卢坤林计算方法。3、预应力锚拉式挡土墙,在预应力作用下,墙体呈现T模式内倾位移,墙背土压力呈现峰值在锚杆位置处的更为明显的抛物线分布,且与预应力呈线性关系,最佳预应力应以墙体位移回到填土前位置作为控制标准,土压力计算推荐采用拟合公式:P=(-16.702h2 +12.836h+ 0.4201)p+K0γz。锚杆最优布置位置为墙体中心,上覆荷载与预应力协同作用下土拱效应峰值与分布范围显著增大。4、随距墙体中心横向距离的增大,锚拉式挡土墙墙背侧向土压力逐渐减小,横向应力拱现象较为明显,其影响范围约为1/3墙宽,且锚杆位置处由于锚杆作用,土拱效应更为明显,土压力衰减最大。
[Abstract]:The magnitude and distribution of the earth pressure in the back of the retaining wall are closely related to the interaction between the soil and the retaining wall. The displacement mode and displacement magnitude of the retaining wall have an important influence on the magnitude and distribution of the earth pressure. The existing anchor and pull retaining wall is mainly used to calculate the earth pressure, which can only be used to calculate the limit state Coulomb earth pressure or Rankine earth pressure. However, the anchor and pull retaining wall is subjected to the lateral restraint of the prestressed anchor. The lateral deformation and displacement of the wall are restricted, and the limit state of the backfill is not reached, and the calculation conditions are quite different from the limit state. In this paper, the method of model test and numerical calculation are used to calculate the earth pressure of anchor retaining wall under non-limit displacement mode. The main conclusions are as follows: 1, cantilever retaining wall, under the action of overlying load, the wall presents T-mode extroversion displacement, the lateral earth pressure on the back of the wall is a parabolic distribution of peak value in the middle of the wall, and the earth pressure is 1.5 times static earth pressure; Under the action of lateral displacement, the wall presents RBT mode displacement, and the lateral earth pressure on the back of the wall presents a nonlinear distribution, which accords with the law of the earth pressure distribution of the rigid retaining wall. Lukunlin calculation method is recommended to calculate the earth pressure, and the unprestressed anchor pull retaining wall is recommended to be used in the earth pressure calculation. Under the action of overburden load, the wall presents T-mode extroversion displacement, and the lateral earth pressure at the back of the wall exhibits parabola distribution of peak value at the position of anchor rod. The recommended height of anchor rod is 0.5H(H as wall height and earth pressure as 0.8 times static earth pressure. Under the action of active lateral displacement, the wall is obliquely inclined in RB mode, and the lateral earth pressure on the back of the wall is also nonlinear distributed. The anchor rod can significantly limit the lateral displacement of the wall. It is also recommended that Lu Kunlin's calculation method .3, prestressed anchor and pull retaining wall be used. Under the action of prestress, the wall presents a T-mode internal displacement, and the earth pressure on the back of the wall presents a more obvious parabola distribution of peak value at the position of the anchor rod. The optimum prestress should take the displacement of the wall back to the position before filling as the control standard, and the fitting formula of the earth pressure should be adopted as the fitting formula: 1 / Pang-16.702h212.836h 0.4201p K0 纬 z. The optimum location of anchor rod is the center of wall. The peak value and distribution range of soil arch effect increase significantly under the synergistic action of overburden load and prestress. With the increase of transverse distance from the wall center, the lateral earth pressure on the back of anchor and pull retaining wall decreases gradually. The phenomenon of transverse stress arch is obvious, the influence range is about one third of the wall width, and the soil arch effect is more obvious and the earth pressure attenuation is the most obvious because of the anchor rod action at the anchor rod position.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU476.4

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