格栅与粉土的拉拔试验研究

根据一般拉拔试验的原理,采用反力架、钢筋焊接试验槽、应力环等设备对格栅与粉土间的拉拔试验做了全面的研究。试验过程中综合考虑了不同的含水量和不同的竖向压力对格栅与土体间摩擦系数的影响,从而得出了不同的摩擦系数。     

黄河淤泥多孔砖砌体的抗压性能试验研究

通过对黄河淤泥多孔砖砌体抗压强度和破坏特征试验结果的对比和分析发现,其具有强度高、开裂晚等特点。从砌体抗压强度、裂缝开展以及破坏特征等方面分析,黄河淤泥多孔砖可以替代黏土砖用作承重墙材。     

新型聚羧酸系超早强复合减水剂试验研究

针对传统早强复合减水剂的缺点,根据功能需要进行设计,利用正交实验方法研究出了一种以聚羧酸系高效减水剂为主体并复合其他早强组分而成的超早强复合减水剂,该减水剂具有无氯离子、无硫酸根、碱含量低,掺量小,减水率高、早期强度发展迅速的特点。     

往返荷载下粗粒土的残余变形特性

结合紫坪铺、瀑布沟和密云土石坝工程,在大型动三轴试验机上(试样尺寸为φ300×750mm),通过往返加荷三轴试验,研究了堆石料和砂砾石料在非饱和状态、饱和排水状态及饱和不排水状态下的残余变形特性,探讨了粗粒土料的密实度、饱水程度、排水条件、初始应力条件及往返加荷条件等对其残余变形特性的影响,并进行了对比分析,得出了一些有工程实用意义的结论.这些研究成果,可作为紫坪铺、瀑布沟和密云土石坝工程进行抗震设计和地震变形分析的基本依据,对其它工程也有重要的参考价值.     

浅析混凝土工程质量事故

对混凝土强度不达标、外加剂使用不当、混凝土裂缝等混凝土工程中容易出现的质量问题、产生原因及防治措施、施工注意事项等方面进行了分析和阐述，供一般混凝土工程施工借鉴。     

测量不确定度在水泥胶砂强度检测中的应用

本文结合检测人员在测量不确定度评定中所遇到的实际问题，找出影响测量结果的所有不确定度来源。对其测量方法进行全面的了解，总结经验，加于探讨.     

Precision of in-place concrete strenghts predicted using core strength correction factors obtained by weighted regression analysis

A two-step method for converting a concrete core compression test result to the in-place strength of the corresponding volume of concrete is presented. The strength of a non-standard core is first converted to the equivalent strength of a standard core, and then the standard core strength is converted to the equivalent in-place strength. Strength correction factors required for these conversions, obtained from weighted linear and nonlinear regression analyses presented elsewhere, are summarized. The accuracy of the predicted in-place strength is affected by the inherent error of the core strength measurement itself, and by the uncertainty of the various strength correction factors. It is shown that confidence intervals on the estimates of the strength correction factors obtained by regression analysis underestimate the true model error because the underlying models are imperfect. Instead, the accuracy of the strength correction factors is determined by a weighted regression analysis of ratios of observed-to-predicted values which accounts for the non-uniform variances of the dependent and independent variables. The coefficient of variation of the in-place strength predicted from a test of a 100 or 150 mm diameter core is between 4 and 5.5.%. If the in-place strength is predicted from a test of a 50 mm diameter core, the coefficient of variation of the predicted in-place strength is approximately 12.5%. These error estimates do not account for possible variation of in-place strength throughout the volume of the element being cored.     

聚氨酯防水涂料的底涂材料的研制

在实验的基础上，分析了聚氨酯防水涂料配套用底涂材料各组分对粘接强度的影响。实验结果显示，在潮湿基面上使用该底涂材料，聚氨酯防水涂膜的基层粘接力大幅度提高，粘接强度可达0．5MPa以上，满足防水工程实际需要。     

预应力混凝土叠合受弯构件刚度评价及挠度计算

分析了二次受力情况下预应力混凝土叠合构件断面的受力特点,探讨了其刚度的评价方法和挠度计算方法。在正常使用状态下,由于预制断面上荷载预应力的存在,增大了断面的有效受压区面积,从而提高了叠合构件的初期抗弯刚度。给出的挠度计算方法合理地解决了二次受力叠合构件的挠度计算问题,其计算结果与试验结果吻合较好。     

Mechanical behavior of micaceous clays

This study aims to investigate the effect of mica content on the mechanical properties of clays.Commercially available ground mica was blended with a locally available clayey soil,at varying nica contents by mass of 5%,10%,15%,20%,25% and 30%,to artificially prepare various micaceous clay blends.The preliminary testing phase included consistency limits and standard Proctor compaction tests.The primary testing program consisted of unconfined compression(UC),direct shear(DS) and scanning electron microscopy(SEM) tests.The test results showed that the liquid and plastic limits exhibited a linear,monotonically increasing trend with increase in mica content.The rate of increase in the plastic limit,however,was found to be greater than that of the liquid limit,thereby leading to a gradual transition towards a non-plastic,cohesionless character.The soft,spongy fabric and high water demand of the mica mineral led to higher optimum water contents and lower maximum dry unit weights with increasing mica content.Under low confinement conditions,i.e.the UC test and the DS test at low normal stresses,the shear strength was adversely affected by mica.However,the closer packing of the clay and mica components in the matrix under high confinement conditions offsets the adverse effects of mica by inducing frictional resistance at the shearing interface,thus leading to improved strength resistance.