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1.
通过宜昌市北海路隧道塌方处理施工的实例，分析了造成塌方的原因，提出并实施了钢拱架、锚喷网复合支护结构塌方处理方案，并对塌空区的回填方案进行了比对，优选泵送陶粒砼加固的新工艺，取得了较好的回填加固效果。通过监控量测成果分析证明了采用陶粒砼工艺大大减轻了回填砼的质量，从而减小了对钢拱架支撑、锚喷复合支护结构的压力，确保回填砼及钢拱架支撑、锚喷复合支护结构的稳定性，确定二次砼衬砌施作的时间。 相似文献
2.
D. Peila 《Geotechnical and Geological Engineering》1994,12(3):145-168
Summary The problem of tunnel face stability is studied and the analysis of the stabilizing effect achieved by pre-reinforcement of the core which has to be excavated is dealt with. In Italy, the insertion of longitudinal fibreglass pipes in the ground has proved to be efficient in solving face instability problems. A thorough review of other applications of the technology has been carried out.The results of a series of parametric, three-dimensional, elasto-plastic finite element analyses are presented. The tunnel excavation with or without support and face reinforcement is simulated in the models. The stresses, plastic zones and displacements in the ground, pipes and lining have been studied. The support effect of the pipes is demonstrated by the results. Face reinforcement significantly reduces the displacements of the face. The stresses in the material at the face are also charged from tension to compression, thus enhancing face stability. 相似文献
3.
泡沫混凝土的单轴和三轴试验研究表明,泡沫混凝土具有较高压缩性和良好延性,可以作为深埋软岩隧道初期支护与二次衬砌之间预留变形层填充材料,分析了其对宜巴高速公路深埋软岩隧道长期稳定性的影响。研究表明,深埋软岩软岩隧道在二次衬砌施工之后依然会产生较大的蠕变变形,单纯依靠提高二次衬砌的厚度,并不能完全控制住围岩的蠕变变形,而且衬砌结构很容易由于变形压力过大而发生破坏。泡沫混凝土预留变形层,可以很好地吸收围岩蠕变变形,缓解二次衬砌承担的蠕变变形压力,减小衬砌的变形,改善其受力,采用厚度较小的二次衬砌即满足隧道长期运营的要求。 相似文献
4.
洞冲里隧道进口处于Ⅴ级围岩地段,该地段地质裂隙发育、地下水丰富,隧道设计在山体的一侧;由于设计未曾考虑偏压的影响,在隧道施工过程中出现隧道边、仰坡面开裂、滑动现象,洞内已经浇注完毕的二衬混凝土出现了开裂、错台;现场监控量测的数据出现拐点,通过研究分析确定为侧压力所致。根据现场的情况经过多个方案的分析、评价、对比后采用了地表斜向注浆长管棚施工方法解决了侧压力问题,取得了很好的效果。 相似文献
5.
非均质黏土地基中平面应变隧道最小支护压力数值模拟 总被引：1，自引：0，他引：1
土体由于沉积而具有天然的非均质性,但关于非均质地基中隧道开挖面稳定性的研究却很稀少,在实际盾构隧道工程中均按均质地基对待。但这一简化并没有考虑非均质性对保持开挖面稳定所需最小支护压力的有利作用,以及对破坏模式的影响。故文中采用基于tresca准则的弹塑性有限元法来研究黏聚力随深度线性变化的纯黏土地基中平面应变隧道的开挖面稳定性,模拟了土体失稳渐进破坏的全过程。最终验证了无量纲化的有效性,得到了各种工况时保持土体稳定的最小支护压力值,并发现了黏聚力线性变化斜率对深埋隧道破坏模式的影响,可为理论分析和工程实践提供依据。 相似文献
6.
以西安地铁一号线朝阳门站一康复路站区段饱和软黄土地铁隧道为研究对象,通过施工期现场地表沉降变形监测,分析了在饱和软黄土特殊地层条件下隧道浅埋暗挖法施工引起的该区段地表沉降变形规律以及地表沉降槽分布特征。结果表明：在饱和软黄土隧道开挖时,随着掌子面的推进,隧道顶地表沉降可分为沉降微小阶段、沉降显著发展阶段、沉降缓慢阶段和沉降稳定阶段;单线隧道开挖后的最大地表沉降量为18．89mm,双线隧道开挖后的最大地表沉降量为36．4mm;已开挖隧道对围岩土体的扰动作用使得后开挖隧道的地表沉降发展较大;双线隧道的地表沉降槽宽度接近单线隧道沉降槽宽度的2倍,因此可以将其近似为单线隧道地表沉降槽宽度与双线隧道轴线中点距离之和;单线隧道开挖后地表沉降槽宽度为8．4～9．3m,双线隧道开挖后地表沉降槽宽度为16．2～17．5m;隧道开挖施工的沉降槽宽度参数为0．435～0．467,单线隧道开挖后的地层损失率为0．765％～1．324％,双线隧道开挖后的地层损失率为1．231％～2．200％。 相似文献
7.
Karl Gunnar Holter 《Rock Mechanics and Rock Engineering》2014,47(3):1003-1020
A composite tunnel lining system based on a sprayed waterproofing membrane combined with sprayed concrete is currently being considered for future Norwegian rail and road tunnels. Possible loading of the tunnel linings caused by water pressure is being investigated. This tunnel lining system consists of a waterproof membrane which, during application on the sprayed concrete lining, bonds mechanically to the sprayed concrete on either side. Hence, a continuous, sealing, and non-draining structure from the rock mass to the interior tunnel surface is formed in the walls and crown. Experiences from some successful recent projects with this lining system in Europe are reviewed. However, these experiences are not directly comparable to the Scandinavian hard rock tunnel lining approach, which utilizes a relatively thin sprayed and irregular concrete layer for permanent lining. When considering the sprayed membrane and sprayed concrete composite lining concept, introducing a partially sealing and undrained element in the lining, the experiences with the traditionally used lining systems in Norway need to be reconsidered and fully understood. A review of several hard rock tunnels with adverse conditions, in which the tunnel lining has been subject to load monitoring, shows that only very small loads in the tunnel linings occur. Recent investigations with in situ water pressure testing, including two sites with the composite sprayed membrane in a partially drained waterproof tunnel lining, are discussed. In a case with a cavern located in a hydraulically saturated rock mass subjected to approximately 8 bar hydrostatic pressure, a negative pressure gradient towards the tunnel lining has been measured. The investigation results from the Norwegian test sites indicate that no significant loading of the tunnel lining takes place in a hydraulically saturated rock when applying this composite waterproof tunnel lining in parts of the tunnel perimeter. 相似文献
8.
Kentaro Yamamoto Andrei V. Lyamin Daniel W. Wilson Scott W. Sloan Andrew J. Abbo 《Computers and Geotechnics》2011
The stability of circular tunnels in cohesive-frictional soils subjected to surcharge loading has been investigated theoretically and numerically assuming plane strain conditions. Despite the importance of this problem, previous research on the subject is very limited. At present, no generally accepted design or analysis method is available to evaluate the stability of tunnels/openings in cohesive-frictional soils. In this study, continuous loading is applied to the ground surface, and both smooth and rough interface conditions are modelled. For a series of tunnel diameter-to-depth ratios and material properties, rigorous lower- and upper-bound solutions for the ultimate surcharge loading are obtained by applying finite element limit analysis techniques. For practical use, the results are presented in the form of dimensionless stability charts with the actual tunnel stability numbers being closely bracketed from above and below. As an additional check on the solutions, upper-bound rigid-block mechanisms have been developed and the predicted collapse loads from these are compared with those from finite element limit analysis. Finally, an expression that approximates the ultimate surcharge load has been devised which is convenient for use by practising engineers. 相似文献
9.
地道塌陷是较为常见的一种地面塌陷灾害,它是先前开挖的人防工程年久失修之后塌陷至地表所致。为减小灾害损失,有效实施治理工程,需要开展详细的灾害勘查工作。本文以实际工作为例,在分析工作区内各类相关地质资料的基础上,通过现场调查,查明地道塌陷灾害的分布现状,然后利用综合地球物理勘探、钻探,钎探和槽探等方法,综合研究分析,准确查明地道的埋藏情况和分布位置。 相似文献
10.
以西安市昆明路地下综合管廊穿越f3地裂缝为研究对象,基于有限元数值模拟分析了地裂缝错动作用下分段地下综合管廊的变形与受力特征。结果表明:地裂缝错动作用下地下管廊顶板竖向沉降变形整体上呈现反“S”形特征,其变形量随地裂缝错动量的增大而增大;管廊结构纵向变形大致可划分3个变形段即下盘翘曲变形段、不均匀沉降段和上盘整体沉降段;在管廊设计使用寿期100 a内地裂缝错动量为50 cm时,管廊接头部位顶板的水平位移在地裂缝带处达到峰值,为4.1 cm,而底板水平位移为3.2 cm,管廊接头部位易发生张开、错位破坏现象,应予以加固;在地裂缝带附近,上盘管廊底板的接触压力减低至0,存在底板脱空现象,应预留注浆孔便于必要时进行注浆加固处理,而下盘管廊底板的接触压力则有明显增大的趋势;当地裂缝错动量超过20 cm时管廊结构顶、底板的拉应变超过了混凝土的极限拉应变,管廊变形破坏模式主要为拉张破坏。研究结果可以为西安市及其他地裂缝发育区地下综合管廊穿越地裂缝带的结构设计提供科学依据。 相似文献
11.
12.
高强防寒保温泡沫混凝土研制与工程应用 总被引：1，自引：1，他引：0
复杂地层寒区隧道填充材料需兼具防寒保温、抗震和优化支护等性能,为解决常规泡沫混凝土在复杂地层寒区隧道应用中存在的不足,通过正交试验得到了自制泡沫混凝土的最佳配合比,研制了一种高强防寒保温泡沫混凝土.通过室内试验,研究了所制泡沫混凝土的保温性能和冻融劣化特征,并采用数值分析方法探讨了西藏嘎隆拉隧道初衬和二衬之间加设泡沫混凝土垫层后的温度场变化规律.结果表明：该泡沫混凝土具有较好的保温性能和抗冻融损伤性能,同时强度、延性较普通泡沫混凝土都有明显改善.数值计算结果显示,当在初衬和二衬之间增设泡沫混凝土垫层时,其相应位置的温度变幅由不设置时的4.5℃变为2℃,最低温度由1℃提高到了3℃,表明加设所研制泡沫混凝土垫层对于阻止围岩受到隧道内冷空气的侵害具有非常显著的效果. 相似文献
13.
Tunnel excavation produces stress changes to the ground and strain to the support lining, leading to the closure (convergence) or instability of the excavated area. Convergence recorded after section excavation is assigned to: (i) strain resulting from the progressive tunnel front advance (face advance effect) and (ii) the time-dependent properties of the soil material (ground creep effect). In the present study, based on the geodetic monitoring records of two recent road tunnels in Greece, a simple methodology to estimate the contribution of each of the two effects is presented. Our analysis reveals that at least half of the total deformation of the examined tunnel sections is due to ground creep, indicating that the major portion of tunnel deformation is due to the time-dependent properties of the ground; a result supported by previous studies from other tunnels as well. 相似文献
14.
着重介绍在景洪水电站左岸下游渣场排水洞开挖施工中，对于Ⅴ类围岩洞段，针对不良地质条件下的隧洞开挖施工技术难点，应用超前小管棚预注浆、格栅钢架(或型钢支撑)、顶拱挂网、系统锚杆、喷射混凝土等多种支护措施，安全顺利地进行隧洞锁口和通过洞身段长达574 m的Ⅴ类围岩洞段，其中还包含3条断层破碎带。 相似文献
15.
巷旁切顶打断了巷道与采场下位顶板的连续性,促进了采场顶板垮落形成碎石帮,深入研究切顶对采场下位岩层垮落特征的影响机制具有重要意义。对采场支架载荷进行了分析,并对上覆岩层建立了力学建模,明确了上覆岩层运动与典型位置采场支架载荷特征的关系。在此基础上,针对6个巷旁切顶的工作面,给出了典型位置支架的载荷数据,从而分析得到巷旁切顶对采场下位岩层垮落特征的影响机制。同时,建立了数值模型,分析了不同的切顶起始位置和下位顶板强度对下位岩层垮落特征的影响。结果表明,121工法的“垮落线”具有对称的弧形边界,110工法的“垮落线”在切顶侧向工作面充分移动,N00工法介于上述两者之间。此外,不同切顶起始位置和顶板强度条件下,切顶的作用效果存在差异。研究结果有利于进一步深化巷旁切顶对采场下位岩层垮落特征影响的认识。 相似文献
16.
清水营煤矿岩体节理与裂隙发育,富水性较好,属于典型的＂三软＂煤层。工作面推进过程中顶板易碎、易冒;煤层开采中,软岩巷道稳定性控制与支护问题,严重制约了该矿井的安全生产。该矿在掘进巷道过断层时,发生突发性漏顶事故,致使巷道停掘。在分析了研究区岩性、构造、地球物理特征以及煤岩的物理力学参数的基础上,针对现场地质条件变化先后采取了两套施工方案对漏顶区进行加固。最终依靠方案二获得了成功,即采用对掘进迎头冒顶区采用水泥、水玻璃浆液加固冒顶区,并对冒空区采用马丽散泡沫充填。施工完成后从迎头退后36m起底,由冒顶区下部通过。现场实践证明,方案二具备安全性与经济性,可为＂三软＂条件下的巷道开采系统设计、岩层控制、安全回采提供地质保障与技术支持。 相似文献
17.
黄土丘陵区房柱式开采地表塌陷特征及机理分析——以陕北府谷县新民镇小煤矿为例 总被引：2，自引：0，他引：2
通过对陕北府谷县新民镇小煤矿采煤地表大面积塌陷的调查和分析,总结出黄土丘陵区房柱式开采地表的塌陷特征,并以西岔沟煤矿房柱式开采为例,对其两种参数顶板岩梁应力、煤柱载荷、煤柱强度进行分析及对比,结果表明合理设计煤柱和煤房尺寸可以防止采煤地表大面积塌陷。 相似文献
18.
湖北清江水布垭导流洞采用矿山法施工,为确保施工安全,以三维有限元对该隧洞处于断层破碎带的进口渐变段的施工过程进行了计算模拟,并根据计算结果确定了合理的施工方案.根据地下结构设计理论中的地层结构法,选用连续体计算模型,对围岩材料和混凝土材料的本构关系分别作理想弹塑性应力-应变关系和线弹性本构关系的简化,并采用摩尔-库仑屈服准则,分析了初期支护结构的受力特点、围岩塑性区的深度和范围以及洞周围岩位移的发展规律.结果显示,围岩塑性区深度较大,而且初期支护结构承受的最大拉、压应力均略大于混凝土的强度极限,指出该区段初期支护结构在采用钢筋格栅喷混凝土的基础上,应加强长、短系统锚杆进行围岩加固. 相似文献
19.
Sounik K. Banerjee 《Geomechanics and Geoengineering》2018,13(2):104-114
Assessment of tunnel stability has become increasingly crucial as more and more tunnels are built in difficult terrains such as sloping ground. The required support pressure on the tunnel walls associates both tunnel stability and liner design considerations. The present analysis attempts to find a uniform internal pressure which can support a circular tunnel built in a sloping ground with a particular level of stability in cohesive-frictional soils. The lower bound finite element limit analysis has been applied to find the required minimum uniform internal support pressure presented as a non-dimensional term p/c; where p is the minimum normal internal pressure on the tunnel boundary to avoid collapse and c is the cohesion of soil. The variation of p/c is presented for a range of normalised embedment depth of tunnel (H/D), stability number (γD/c), internal friction angle of soil (?) and slope angle (β); where H is the crown depth of the tunnel, D is the tunnel diameter and γ is the unit weight of soil. Appropriate comparisons have been carried out with available literature. Failure patterns of the tunnel have also been studied to understand the extent and the type of failure zone which may generate during the collapse. 相似文献