盾构隧道斜穿Ⅳ级地裂缝段管片力学性能研究

目前西安地铁穿越地裂缝段采用浅埋暗挖法,在结构上采用特殊措施,该种施工方法及应对措施基本是有效的。明挖法尽管有许多优点,但西安地裂缝也多分布于城区内,未见采用明挖法穿越地裂缝段案例。两种施工方法存在施工条件不允许、工期长、施工风险大、成本高等突出问题。为提高西安地铁在穿越地裂缝段的施工安全性、快速性、经济性,提出采用盾构法施工斜穿西安市Ⅳ级地裂缝。通过数值模拟,对盾构隧道斜穿Ⅳ级地裂缝段的管片力学性能进行研究。研究表明,目前采用的普通钢筋混凝土管片不能满足斜穿Ⅳ级地裂缝的要求,在对管片结构形式、防水材料、施工工艺采取相应改进后,发现异形加厚管片在地裂缝段具有较强的通过性,施工安全及经济性较传统浅埋暗挖法具有较强优势。

Mechanism of formation of sliding ground fissure in loess hilly areas caused by underground mining

Based on a shallow-buried coal seam covered with thick loose layers in hilly loess areas of western China,we developed a mechanical model for a mining slope with slope stability analysis, and studied the mechanism of formation and development of a sliding ground fissure by the circular sliding slice method.Moreover, we established a prediction model of a sliding fissure based on a mechanical mechanism,and verified its reliability on face 52,304, an engineering example, situated at Daliuta coal mine of Shendong mining area in western China. The results show that the stress state of a mining slope is changed by its gravity and additional stress from the shallow-buried coal seam and gully terrain. The mining slope is found to be most unstable when the ratio of the down-sliding to anti-sliding force is the maximum, causing local fractures and sliding fissures. The predicted angles for the sliding fissure of face 52,304 on both sides of the slope are found to be 64.2° and 82.4°, which are in agreement with the experimental data.

WSS注浆加固在地铁隧道的施工控制与应用

本文依托西安市地铁二号线会展中心~韦曲南段TJSG-23标段三爻站~凤栖原站区间暗挖隧道工程实例,论述了WSS工艺注浆加固土体止水堵漏在黄土地层地铁隧道中的施工技术控制与应用。WSS工艺注浆具有适应范围广、施工工艺简便、施工周期短、质量容易控制、加固土体及止水堵漏效果尤其显著、经济易行等特点。WSS工艺注浆对黄土地层有较好固结止水效果,且浆液渗透能力强,固结速度快,整体稳定性较好,通过注浆加固形成一道有效的帷幕止水固结带。浆液混合方式和注浆的方向性可随时调节,注浆材料的凝胶时间可以实现从瞬结到缓结,配比可任意搭配。尤其对于湿陷性黄土地层加固及止水堵漏效果明显,在西安地铁加固土体止水堵漏施工中得到了很好的应用与技术控制,此工艺可以为类似工程提供参考。