海底地磁日变观测站的设计与应用

采用布设海底地磁日变观测锚系的技术方法,可解决远海区磁测日变改正观测资料问题。重点介绍设立海底地磁日变观测锚系中观测设备的技术特性、锚系设计及这一技术方法在国内的首次应用情况。     

小湾水电站地下厂房岩锚梁现场试验研究

小湾水电站地下厂房是目前世界上最大的地下厂房之一,采用了岩锚吊车梁结构形式,厂房开挖跨度和高度分别为 28.30 m和79.88 m。由于岩锚梁通过两条宽度为0.5～8.5 m的陡倾断层,其施工期与运行期的稳定性成为关注的问题之一。在厂房洞室群的尾水闸门室中,选择具有相似工程地质条件的区域进行了现场模型试验研究,包括主要监测仪器的布置和加卸载过程设计,并对监测结果进行了分析。模型试验表明岩锚吊车梁承载能力满足设计要求,安全性有保障。     

锚固体应力分布规律的数值模拟分析

采用非线性有限元法,分析了全长粘结式锚杆在荷载作用下剪应力的分布规律,同时研究了被加固岩土体的性质对锚固体剪应力分布规律的影响。并将数值模拟的结果与理论计算以及试验结果进行了对比分析。分析表明,锚固体剪应力的分布非常不均匀;当荷载不大时,锚杆所受的剪应力分布范围较小,而最大剪应力数值较大;随着荷载的加大,剪应力的分布范围有向下扩展的趋势,但扩展的速度比较慢;锚固体所受的剪应力的大小和分布与岩体性质有密切的关系,岩石越坚硬,剪应力分布越集中,最大剪应力的数值越大;而岩体越松软,剪应力分布就越均匀,最大剪应力的数值就越小。     

喷锚支护技术在昆明市深基坑工程中的应用

喷锚支护已在昆明市深基坑工程中得到广泛的应用 ,本文简述喷锚支护基本原理和施工工艺 ,并针对昆明市区地层特点 ,介绍近期所采用的相应施工措施。     

广州市荟雅苑基坑支护及事故处理

广州市荟雅苑的基坑支护除北边采用土钉墙和桩锚联合支护外,另外三边均做放坡处理,施工过程中,发生了护壁一处土体被水掏空、土钉钢筋出露,基坑被水掩没的事故,事故原因：（１）土钉支护在软弱地层中有局限性;（２）土钉支护与北边排水沟渠湘同时施工,产生安全隐患,（３）天降暴雨;（４）临临应急排水措施不当,事帮经紧急处理,测量证明土钉支护仍然是成功的,但也提醒人们在基坑支护施工中,必须加强动态管理,注意信息化施工,重视水对基坑稳定所构成的影响。     

老粘性土中某喷锚滑坡事故的分析及处理

介绍了老粘性土层中某喷锚的滑坡事故,并根据滑坡体的形态,进行了反演计算,分析了滑坡原因。该滑坡的分析和处理为今后老粘性土层中喷锚的设计和施工提供了有益的启示。     

岩石锚桩基础的承压力与抗拔力之应用

根据“110kV绩溪-旌德”线路现场设计及施工情况,系统总结了岩石锚桩基础在中风化、强风化的山区中的应用经验,分析了工程设计中锚筋内力、锚桩承载力和粘结力之间关系,合理采用计算公式,获得较好效果。     

喷锚与桩锚支护在中南花园酒店深基坑工程中的应用

针对中南花园酒店深基坑极为复杂的地质条件和周边环境,采用喷锚与桩锚联合支护的方案,保证了基坑施工和周边建筑物及地下管线的安全,降低了工程成本,缩短了工期,可为类似工程的设计与施工提供借鉴。     

深部软岩巷道锚注支护数值模拟研究

采用大型有限元数值模拟软件ANSYS,对深部软岩巷道锚注支护前后围岩变形破坏规律进行了数值模拟,对锚注支护前后围岩的应力、位移及塑性区的变化情况等进行了系统分析,结果表明,锚注支护显著提高了围岩的强度和承载能力,有效地控制了深部软岩巷道的损伤变形。     

Uplift of symmetrical anchor plates by using grid-fixed reinforced reinforcement in cohesionless soil

Uplift response of symmetrical anchor plates with and without grid fixed reinforced （GFR） reinforcement was evaluated in model tests and numerical simulations by Plaxis. Many variations of reinforcement layers were used to reinforce the sandy soil over symmetrical anchor plates. In the current research, different factors such as relative density of sand, embedment ratios, and various GFR parameters including size, number of layers, and the proximity of the layer to the symmetrical anchor plate were investigated in a scale model. The failure mechanism and the associated rupture surface were observed and evaluated. GFR, a tied up system made of fiber reinforcement polymer （FRP） strips and end balls, was connected to the geosynthetic material and anchored into the soil. Test results showed that using GFR reinforcement significantly improved the uplift capacity of anchor plates. It was found that the inclusion of one layer of GFR, which rested directly on the top of the anchor plate, was more effective in enhancing the anchor capacity itself than other methods. It was found that by including GFR the uplift response was improved by 29%. Multi layers of GFR proved more effective in enhancing the uplift capacity than a single GFR reinforcement. This is due to the additional anchorage provided by the GFR at each level of reinforcement. In general, the results show that the uplift capacity of symmetrical anchor plates in loose and dense sand can be significantly increased by the inclusion of GFR. It was also observed that the inclusion of GFR reduced the requirement for a large L/D ratio to achieve the required uplift capacity. The laboratory and numerical analysis results are found to be in agreement in terms of breakout factor and failure mechanism pattern.