重组竹格栅式条形基础承载力计算方法研究

Research on Calculation Method for Bearing Capacity of Bamboo Scrimber Grille Strip Foundation

重组竹作为一种新兴的绿色建筑材料,以其绿色环保、轻质高强、耐腐蚀和易加工装配等优点成为广大学者的研究重点,以重组竹作为结构承重构件的项目不断落地.针对村镇建筑低荷载和低层数的特点,提出一种以重组竹为材料,适用于上部结构形式为竹木结构的格栅式条形基础,并对其开展结构选型和优化设计.开展了砂土地基中基础底面开孔率为0和24%的格栅式条形基础的土工离心机模型试验,揭示了基础底面开孔对地基极限承载力、基底压力和土体附加应力的影响规律.试验结果表明,基础底面开孔对极限承载力和基底压力的分布影响显著,但对土体附加应力的分布无明显影响.通过有限元计算方法模拟了砂土中格栅式条形基础的竖向承载特性,并且有限元计算得到的荷载-位移曲线和基底压力分布规律与离心机模型试验值结果吻合良好,证明了有限元方法的正确性.采用经验证的有限元方法对不同开孔率下格栅式条形基础的承载性能进行了系统研究,计算得到了不同密实度砂土地基中不同开孔率的格栅式条形基础的地基极限承载力,并与太沙基极限承载力计算结果进行了对比,引入开孔率概念,得到考虑开孔影响的格栅式条形基础的地基极限承载力计算方法.

As an emerging green building material,bamboo scrimber is becoming a research focus of scholars owing to its advantages such as green environmental protection,light weight,high strength,corrosion resistance,and easy processing and assembly.Therefore,the projects with load bearing elements made of bamboo scrimber are continuously carried out.Aimed at the characteristics of village buildings including low load and a small number of floors,a grille strip foundation with bamboo scrimber as the material is proposed this paper,which is suitable for buildings whose upper structures take the form of a bamboo and wood structure.Moreover,the structure selection and optimization design are performed.The geotechnical centrifuge model tests of grille strip foundation with opening ratios of 0 and 24%were conducted in sandy soil foundation,and the influences of foundation bottom opening on the ultimate bearing capacity,foundation pressure and additional stress in soil were revealed.Test results show that the foundation bottom opening had a significant effect on the distribution of ultimate bearing capacity and foundation pressure,but it had no obvious effect on the distribution of additional stress in soil.The vertical bearing characteristics of the grille strip foundation in sandy soil were simulated using the finite element calculation method,and the obtained load-displacement curve and foundation pressure distribution law were in good agreement with the test results of the centrifuge model,thereby verifying the finite element method.The bearing performance of grille strip foundation with different opening ratios was systematically studied using the verified finite element method,and the ultimate bearing capacities of grille strip foundation with different opening ratios in sandy soil foundation with different values of compactness were calculated,which were also compared with those calculated by the Terzaghi formula.In addition,the concept of opening ratio was introduced,and a calculation method for the ultimate bearing capacity of grille strip foundation considering the influence of opening was given.