深海吸力锚水平极限承载力研究

深海吸力锚基础的极限承载能力是海洋工程锚固系统的一个关键问题。基于Coulomb摩擦接触对原理,给出一种模拟吸力锚承载能力的有限元模型。在该数值模型基础上,利用通用有限元分析软件ABAQUS,研究系泊点位置、吸力锚长径比对极限承载力的影响,并给出深海吸力锚失稳模式。结果表明,系泊点位置极大地影响着吸力锚的极限承载力与稳定性,系泊点位置的变化会导致吸力锚出现前倾转动、平移滑动和后仰转动失稳模式,同时吸力锚失稳模式受长径比的影响。为工程实际和理论分析提供了技术支持和理论指导。     

基于双曲线模型的冻土中锚杆荷载传递特性研究

为研究不同冻结温度及含水率对冻结粉土中锚杆抗拔性能的影响,根据冻土与混凝土接触面的力学特性和变形规律,采用双曲线模型描述锚杆-冻土接触面的剪切特性。基于荷载传递法,建立考虑温度和含水率影响的锚杆荷载传递方程,采用有限差分法进行求解,得到锚固段的剪应力、轴力及承载力计算式;通过ABAQUS数值模拟验证荷载传递方程的合理性,结合算例分析表明：冻土中锚杆抗拔承载力大于常温土,且温度越低承载力越高;在相同荷载作用下,冻土温度越低,轴力沿深度衰减越快,剪应力分布越不均匀;相同冻结温度下,锚杆承载力随含水率的增大呈先增大后减小的趋势;增加锚固体直径能有效地提高锚杆的极限承载力。     

Seismic uplift capacity of inclined strip anchors in sand using upper bound limit analysis

Pseudo-static approach is adopted in this paper to determine the seismic uplift capacity of an inclined strip anchor using upper bound limit analysis. Two different failure mechanisms are considered to obtain the magnitudes of unit weight component of uplift factor f_γE for different values of soil friction angle, interface friction of anchor plate, anchor inclination, embedment ratio and horizontal seismic acceleration coefficient. The failure mechanism 1 consists of a triangular and quadrilateral rigid blocks; whereas the failure mechanism 2 comprises a logarithmic spiral failure zone with varied focus, sandwiched between a triangular and quadrilateral rigid blocks. It is observed that the magnitude of uplift factor f_γE decreases significantly with the increase in seismic acceleration but increases with the increase in embedment ratio and roughness of the anchor surface. However, a mixed trend in the values of f_γE can be observed for different inclination of the anchor, which is clearly discussed in this paper. The results are compared with the existing values in the literature and the significance of the present methodology for designing the inclined strip anchor is discussed.     

福建闽侯某小区滑坡特征及成因机制分析

通过对福建闽侯某小区滑坡的地质调绘、探井及钻孔勘察等综合方法应用,结合深部位移监测,充分论证了滑面的位置,分析研究滑坡的基本特征及影响因素。研究表明,该滑坡是推移式土质滑坡,破坏模式为蠕滑-拉裂-弯曲型式,结合小区建设实际,提出切合实际且有效的锚索抗滑桩的治理方案。     

辽宁海州露天矿边坡预应力锚索远程监测系统

随着海州露天矿的闭坑,岩体结构越来越弱化,围岩的支承能力越来越小,露天矿边坡处于不稳定状态,具有发生大规模滑坡的潜在危险。根据海州露天矿工程地质条件,边坡形态,稳定状态及监测目的,研发海州露天矿边坡预应力锚索远程监测系统。系统应用GPRS远距离无线传输技术远程主动监测边坡岩体内部应力变化来获取岩体变形特征和滑移信息,实现边坡锚索应力全天候连续自动监测,其采用太阳能进行供电,适用于边坡中、长期监测。通过对海州露天矿边坡监测与边坡稳定性分析的现场应用实践证明,该系统可以对边坡稳态进行实时监测,对边坡滑坡灾害防治具有重要意义。     

The modelling of anchors using the material point method

The ultimate capacity of anchors is determined using the material point method (MPM). MPM is a so‐called meshless method capable of modelling large displacements, deformations and contact between different bodies. A short introduction to MPM is given and the derivation of the discrete governing equations. The analysis of a vertically loaded anchor and one loaded at 45° is presented. The load–displacement curves are compared to that obtained from experiments and the effect of soil stiffness and anchor roughness is investigated. The results of the vertically loaded anchor are also compared to an analytical solution. The displacement of the soil surface above the anchor was measured and compared to the numerical predictions. Convergence with mesh refinement is demonstrated and the effect of mesh size and dilatancy angle on the shear band width and orientation is indicated. The results show that MPM can model anchor pull out successfully. No special interface elements are needed to model the anchor–soil interface and the predicted ultimate capacities were within 10% of the measured values. Copyright © 2005 John Wiley & Sons, Ltd.     

滑坡治理中格构式锚杆框架结构设计

结合略阳县城狮子山滑坡的治理，讨论了格构式锚杆框架结构治理松散堆积体滑坡设计的全过程。根据防治区的工程地质情况和相应的规范要求，确定了防治工程的安全等级。利用格构式锚杆框架结构所采用的小间距、小吨位锚杆及连续格构梁柱．从而使格构梁柱受力较均匀，适合松散堆积体滑坡治理的需要，即同时满足深层抗滑和浅层护坡。给出了坡面推力的计算模型和计算公式．对于格构式锚杆框架结构中的格构梁柱、锚杆和框架间面板也分别给出了相应的结构设计方法和公式．再就施工中应注意的事项给出了明确的建议和要求。     

剪切位移传递法分析抗浮锚杆应力状态

假定锚侧摩阻力与剪切变形呈非线性变化,考虑锚侧土体在影响区域内符合非线性弹性理论,运用剪切位移传递法,建立了抗浮锚杆计算模型,推导了锚侧剪应力与剪切位移的关系式。通过模型描述受荷状态下抗浮锚杆的轴力、摩阻力、位移的变化形态,分析了锚杆应力变化的工作机理,并预估了其极限承载力。     

武警湖北省总队团职楼深基坑设计与施工

针对武警湖北省总队团职楼深基坑极为复杂的地质条件和周边环境,采用桩锚、锚喷网、放坡挂网喷砼和双排粉喷桩的联合支护方案,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,取得了很好的经济效益和社会效益。     

劲性桩在芜湖世茂滨江花园淤泥质软土深基坑中的应用

对深基坑支护设计中几种方案从安全、造价、适用性等诸多方面进行对比、方案选型和优化,力求设计及施工方案具备安全、经济、适用及工期合理等优点,以便控制基坑支护工程位移和沉降,满足对周边环境保护要求。