深层搅拌法在广州大学城软基处理中的应用

分析了广州大学城某建设场地地基处理方案的选取和优化设计,从施工参数、施工工艺、施工控制及检测四个方面介绍了深层搅拌法的施工过程及地基处理效果,得出了几个有益的结论,可供同类工程参考。     

水泥搅拌桩在软土地基加固的应用

本文通过工程实例。论述了沿海软土地基的多层建筑应用水泥搅拌拉加固地基是一种较为理想的办法。     

深层搅拌法结合土工格栅处理软基的应用

结合工程实例,介绍了“深层搅拌法结合碎石间隔土夹土工格栅”在软基处理中的应用,总结了该方法的适应条件和施工注意事项,并通过该工程几种软基处理方案的对比和工后效果检验,说明该方案在特定土层中的有效性。     

钉形搅拌桩与常规搅拌桩加固软土地基的对比研究

针对国内水泥土搅拌桩应用中存在的技术问题,介绍了笔者研制的钉形水泥土搅拌桩及其施工工艺。通过江苏省高速公路钉形搅拌桩与常规搅拌桩加固软土地基的试验段工程,分别进行了载荷试验、标准贯入试验、芯样的无侧限抗压强度试验;进行了路堤荷载作用下的沉降、深层水平位移、超静孔压、荷载传递等监测,从桩身强度、成桩质量、荷载传递、加固效果等方面对钉形搅拌桩与常规搅拌桩加固软土地基进行了对比研究,论证了钉形搅拌桩加固软土地基的优越性和经济性,结果表明,钉形水泥土搅拌桩具有很好的工程应用前景。     

Performances of SDCM and DCM walls under deep excavation in soft clay: Field tests and 3D simulations

This study presents the results of full-scale tests and three-dimensional finite element analyses of deep cement mixing (DCM) and stiffened deep cement mixing (SDCM) columns under lateral loads and DCM and SDCM walls under deep excavation in soft clay. The DCM walls used in this study comprised one, two and three rows of DCM columns, whereas the SDCM walls consisted of only one row of DCM columns with steel H-beams inserted in either all DCM columns or in alternating DCM columns. The measured and simulated results are presented in terms of profiles of lateral displacement, settlement and bending moment.     

深层搅拌法加固地基设计及工程应用

对深层搅拌法加固软土地基的特点、适用性以及加固原理进行了阐述,以设计准备、设计参数、设计承载力及沉降值为目标,对深层搅拌加固进行了详细设计。将设计应用于具体工程实例,分析了实际工程的加固效果,根据设计及计算结果可知,利用深层搅拌法进行加固处理后,软土地基的承载力及强度得到了很大的提升。     

挤密碎石桩在桥头软基处理中的应用

基于工程实践及分析研究本文首先介绍挤密碎石桩在桥头软基处理中的成功应用 ,其次提出确保了挤密碎石桩干振施工法及其工程质量保证措施。最后 ,根据现场跟踪检测的资料进行分析 ,验证采用挤密碎石桩处理高速公路桥头软基是可行、合理、方便和经济的 ,以供使用参考     

水泥土搅拌桩加固海相软土地基的应用研究

根据工程实践经验,为保证水泥土搅拌桩的质量以及复合地基的加固效果,对水泥土搅拌桩加固厦门海相软土地基的应用研究进行了探讨,并得出了一些有益的结论,提出了相关建议,具有参考价值。     

Discussions on rockburst and dynamic ground support in deep mines

The paper is a summary of discussions on four topics in rockburst and dynamic ground support.Topic1 is the mechanisms of rockburst.Rockburst events are classified into two categories in accordance with the triggering mechanisms,i.e.strain burst and fault-slip burst.Strain burst occurs on rock surfaces when the tangential stress exceeds the rock strength in hard and brittle rocks.Fault-slip burst is triggered by fault-slip induced seismicity.Topic 2 is prediction and forecasting of rockburst events.Prediction for a rockburst event must tell the location,timing and magnitude of the event.Forecasting could simply foresee the probability of some of the three parameters.It is extremely challenging to predict rockbursts and large seismic events with current knowledge and technologies,but forecasting is possible,for example the possible locations of strain burst in an underground opening.At present,the approach using seismic monitoring and numerical modelling is a promising forecasting method.Topic 3 is preconditioning methods.The current preconditioning methods are blasting,relief-hole drilling and hydrofracturing.Defusing fault-slip seismicity is difficult and challenging but has been achieved.In very deep locations(3000 m),the fracturing could extend from the excavation face to a deep location ahead of the face and therefore preconditioning is usually not required.Topic 4 is dynamic ground support against rockburst.Dynamic ground support requires that the support system be strong enough to sustain the momentum of the ejecting rock on one hand and tough enough on the other hand to absorb the strain and seismic energies released from the rock mass.The current dynamic support systems in underground mining are composed of yielding tendons and flexible surface retaining elements like mesh/screen and straps.Yielding props and engineered timber props are also used for dynamic support.     

深厚软土水泥搅拌桩复合地基沉降分析及控制

深层水泥搅拌桩是处理深厚软土地基的有效方法。本文结合温州地区典型深厚软土 ,首先分析了采用水泥搅拌桩加固的4～ 8层建筑物地基的长期沉降观测结果 ,并用传统的方法进行了沉降计算 ,发现计算结果是实测结果的 3倍左右。然后 ,试验研究了典型温州软土的结构性 ,得出主要压缩层的土体结构屈服应力比在 1 7～ 2 5范围内 ,发现当下卧层的附加应力σz 与有效自重应力σz0 ′之和小于土体结构屈服应力σsy 时 ,建筑物沉降将得到有效控制。最后 ,在前人研究工作的基础上 ,提出考虑软土结构性的沉降计算方法 ,考虑土的结构性对下卧层沉降的影响 ,对 12幢不同层数的建筑物进行了沉降计算 ,计算结果与实测结果相当一致。