摘要
人工挖孔桩是一种用人力挖土、现场浇筑的钢筋混凝土桩。该桩体广泛适用于无水或少水且较密实的土或岩石地层,孔深不宜大于15 m。在松散土体上增设人工挖孔桩可以大幅提高土体的有效应力,表现为粒间应力增加,提高土体整体性,理论上是一种治理塌方的优良手段。但目前人工挖孔桩在治理塌方问题上的研究较少,基于此现状,文章以杜家沟隧道为依托,对进口段两侧边坡设置2 m×3 m(横×纵)加固方桩,桩长23 m。右侧2根,长23 m;左侧1根,长20 m,隧道中心线与左右两侧桩中心距为7.2 m,右侧第二根桩与第一根桩中心间距4 m布设。通过Plaxis2D有限元分析软件对隧道纵断面与横断面进行分析,验证人工挖孔桩在治理塌方时的可行性。结果表明,加设人工挖孔桩后,横断面总位移减少,靠近桩布置位置上的位移减少的最为明显,有效应力大幅增加,且分布更加均匀;加设人工挖孔桩后,纵断面与横断面的有效应力增加,总位移减小,表明该方案布设的抗滑桩合理,可以为今后的相似工程提供依据;在开挖稍有扰动就快速松动坍塌地质条件下的浅埋隧道,可以使用人工挖孔桩使浅埋隧道变形减小,并使岩土体整体性提高。
Manual hole-digging pile is a kind of reinforced concrete pile which is excavated by manpower and poured on site. The pile is widely used in dense soil or rock strata without water or less water, and the hole depth should not be more than 15 m. The installation of artificial hole-digging pile on loose soil can greatly increase the effective stress of soil,which is characterized by the increase of intergranular stress and the improvement of soil integrity and is therefore an excellent means to control collapse in theory. At present, however, there is little research on manual hole-digging pile in the treatment of landslide. Thus, based on the Dujiagou Tunnel, this paper sets up 2 m×3 m(horizontal×vertical) reinforced square piles on both sides of the entrance section, and the pile length is 23 m, with 2 piles of 23 m in length on the right, and 1 pile on the left, 20 m in length, and the distance between the center line of the tunnel and the piles on the left and right sides is 7.2 m, and the distance between the second pile and the first pile on the right is 4 m. The tunnel profile and cross section are analyzed by Plaxis2D finite element analysis software to verify the feasibility of manual holedigging pile in the treatment of collapse. The results show that, after the manual hole-digging pile is added, the total displacement of the cross section decreases, the displacement near the pile layout decreases most obviously, the effective stress increases greatly, and the distribution is more uniform;after adding manual hole-digging pile, the effective stress of profile and cross section increases and the total displacement decreases, which indicates that the anti-slide pile arranged in this scheme is reasonable and can provide a basis for similar projects in the future;for the shallow tunnel under the geological condition of rapid loosening and collapse with a little disturbance in excavation, manual digging piles can be used to reduce the deformation of the shallow tunnel and improve the integrity of rock and soil.
出处
《科技创新与应用》
2022年第25期85-89,共5页
Technology Innovation and Application
