基于层次分析的可拓学理论围岩大变形预测方法及应用

围岩大变形是地下工程建设中地质灾害的一种,为探讨准确而快速地预测围岩大变形,文章将层次分析法和可拓学理论方法与围岩大变形预测相结合,建立了基于层次分析的可拓学理论围岩大变形预测方法。该方法是在物元理论、可拓集合论和关联函数运算的基础上,通过选取能够反映和体现围岩大变形的几项重要参数指标(本文选取岩石单轴抗压强度、主应力值、强度应力比、弹性模量四项指标),建立围岩大变形预测的物元模型,结合层次分析法来确定各因素的权重值,通过实际围岩大变形等级的关联度计算,最终确定围岩大变形等级;并与模糊层次分析法取得的围岩大变形结果进行对比分析。该方法能够运用一定的基础数据对围岩大变形作出预判,对工程建设可起到一定的指导作用。     

水平旋喷在饱和粉细砂围岩中的应用

水平旋喷利用高压射流浆液破碎围岩并通过旋转搅拌将水泥浆与围岩充分混合搅拌,形成柱状固结体,解决注浆无法达到充分渗透处改善围岩的目的.文章通过分析水平旋喷桩施工难点及适用地质条件,并介绍孔口止水装置在旋喷施工中的应用,以及解决跑浆塌孔断桩现象,为软流塑饱和粉细砂围岩提供有效的施工参考.     

对软弱围岩隧道施工方法及施工工艺措施的探讨

根据当前软弱围岩中公路隧道常用施工方法,采用数值计算并综合考虑各种因素,对软弱围岩隧道的开挖方式进行研究,从而得出在软弱围岩中隧道施工合理的开挖方法,并提出了相应施工措施;结合实际工程,通过监控量测,证明了其施工方法及工艺的合理性。     

高压旋喷法处理高速公路软土地基

结合实际工程,介绍了高压旋喷注浆法加固高速公路软土地基,叙述了其在处理公路软弱地基工程中的设计计算过程、施工工艺并分析了加固效果,,证明这种加固方法可以应用于高速公路的软土路基加固工程中.     

浅谈公路软土地基处理

公路是线形带状的特殊人工建筑物,不可避免地经过不同的地质地区,也必然会遇到软土地质地区,若基底承载力不能满足设计要求,就需要进行软基处理。本文引用了10余篇文献,系统概括了软土地基处理方案,并总结了各种具体方法的适用条件,对出现的新方法、新工艺作了简单介绍。     

浅谈沈抚高速公路软基处治方法

公路路基的强度、稳定性和耐久性直接影响道路的质量和使用性能,通过沈抚高速公路建设的实践,提出了对软土路基的处治方法。     

Modelling upheaval buckling in marine buried pipelines by coupling the shear stresses and soft soil stiffness

Buried marine pipelines employed in the Oil & Gas industry are subjected to pressure and temperature gradients, which cand produce local high compression loads leading to the onset of upheaval buckling failure. Upheaval buckling occurs when the localized stresses across the pipeline are high enough to induce constant deformation due to the low soil restriction in the upward direction. Therefore, models to predict upheaval buckling in buried marine pipes caused by high pressure and high temperature (HP/HT) and soil stiffness have been developed based on Euler-Bernoulli beam theory (EBT). However, this theory does not consider stresses and strains due to shear stresses which can play an important role in upheaval buckling failure. Therefore, in this work an analytical model that takes into account Engesser-Timoshenko beam theory (TBT) and considers the shear effects on pipelines was developed to predict upheaval buckling in buried marine pipelines. Furthermore, equations that govern vertical buckling of buried pipelines considering a plastic soil with initial imperfection were considered. Analytical results were compared with finite element models of buried pipeline and other models reported in the literature, and it was observed that analytical results fall in the range of those reposted in the literature. It was also observed that the incorporation of shear stresses in buried marine pipelines has low effect on upheaval buckling onset and propagation, but the soil stiffness has a strong influence on upheaval failure in buried marine pipelines.     

Design and model test of a soft-connected lattice-structured floating solar photovoltaic concept for harsh offshore conditions

Various types of floating solar photovoltaic (FPV) devices have been previously proposed, designed and constructed with applications primarily limited to onshore water bodies or near-shore regions with benign environmental conditions. This paper proposes a novel FPV concept which can survive harsh environmental conditions with extreme wave heights above 10 m. This concept uses standardised lightweight semi-submersible floats made of circular materials as individual modules. The floating modules are soft connected with ropes to form an FPV array. We first present the conceptual design of the floats and the connection systems, including hydrostatic, hydrodynamic, and structural assessments of the floats. To verify the motion response performance, we carried out 1:60 scaled model tests for a 2 by 3 array under regular and irregular wave conditions. From the time series and response spectra, the motion characteristics of the array and the mooring responses are analysed in detail. The proposed concept exhibits excellent performances in terms of modular motions with limited wave overtopping and no contact is observed between adjacent modules under the extreme wave conditions. The findings of this study can serve as a valuable reference to developing reliable and cost-effective FPV technologies for offshore conditions.