混凝土强度预测与设计的神经网络方法

首次提出混凝土强度预测与设计的神经网络方法。对普通混凝土、高强混凝土等多种混凝土建立了表现混凝土强度因果规律的神经网络方法，在已有混凝土试验资料基础上，进行了强度预测。与通用的回归分析方法所得结果对比，神经网络方法精度较高。通过实例给出了应用神经网络方法的强度预测结果。表明神经网络是混凝土强度，特别是高强混凝土强度预测和设计的崭新途径     

水工预应力钢筋砼迭合构件正截面抗裂度研究

本文通过对二次受力预应力钢筋砼迭合梁受力性能分析,研究了荷载预应力、预应力损失分期进行、钢筋应力超前和砼应变迟后现象等因素对其正截面抗裂度的影响。文中提出了适合水工预应力钢筋砼迭合梁抗裂度计算的方法,供修订《水工钢筋检结构设计规范》(SDJ20—78)时参考。     

JMP防水密实剂研究

JMP防水密实剂是一种多功能的复合外加剂。能改善混凝土(以下混凝土简写为砼的)和易性,提高砼的强度,提高抗裂抗渗等性能。该产品具有生产工艺简单、施工方便、成本低廉、是地下防水砼的理想外加剂。     

丝胶层状结构及溶解特性的研究

本文研究了丝胶聚集态结构和溶解特性,指出绢丝腺不同部位分泌的丝胶蛋白质组分有差异,并以保持层状的方式堆积覆盖在丝素表面;构成丝胶难溶性部份的蛋白质组分在易溶丝胶中也大量存在;鲜茧茧丝外层易溶丝胶主要以溶胀溶解方式脱落,内层难溶丝胶主要以水解方式脱落;在不同溶解条件下,外层易溶丝胶的溶解方式也有差异;通过适当处理,可使茧丝最外层易溶丝胶难溶化,而不改变中层丝胶的易溶性。     

Strain energy release rate at interface of concrete overlaid pavements

A new method for calculating energy release rate (ERR) at the interface of concrete overlaid pavements is proposed using crack closure and the nodal force technique. This method transforms a 3D pavement system into a 2D interfacial crack model via a theoretical conversion. The interfacial ERRs of steel fibre-reinforced, roller-compacted, polymer-modified concrete overlay pavement subjected to vehicular load were calculated and compared with the measured interfacial fracture toughness of the bi-material. It was found that the ERRs considerably decrease with the increase in overlay thickness and elastic modulus of foundation. Thin overlays (less than 100 mm) should not be considered in overlay pavement design to avoid interfacial delamination induced by heavy vehicular loading. For a typical overlay pavement system subjected to complex vehicular loads, an interfacial crack suffers mainly from damage due to mode-I, opening, compared to mode-II, sliding, while mode-III, tearing damage is negligible.     

混凝土防护材料应用性能研究

混凝土防护材料对混凝土结构的耐久性能具有重要的影响。本文利用模拟试验,通过遴选当前国内使用较广泛的七种典型防护材料进行对比试验。研究结果表明,水泥基渗透结晶防水型涂料对混凝土的防护效果最好,氟碳类防护材料表现次之。     

主从结构的双时态数据模型的设计应用

针对医院信息管理系统（ HIS）中的时态信息处理需求,提出了一种具有主从结构的双时态数据模型,进一步,对该模型的时态实体完整性、时态参照完整性以及用户定义的时态完整性进行了分析和设计。实际应用表明,新模型不仅具有良好的数据完整性约束机制,而且还易于实现时态数据的分段储存。     

结构缝对高碾压混凝土拱坝地震破坏机理影响的试验研究

为探究结构缝的存在对碾压混凝土拱坝地震破坏机理的影响,在地震模拟系统上进行了拱坝模型动力破坏试验。模型的建立基于弹性力-重力准则,不考虑库水以及坝体-地基相互作用。采用一种新型压电传感器测量模型内部的动态应力,并主动监测模型内部微裂纹的发生和发展过程。横缝的模拟考虑了键槽的影响,诱导缝的模拟基于断裂力学理论。选择模型基频对应的谐波逐级加载来研究拱坝在地震动超载作用下的反应。试验表明,拱坝顶拱的端部与拱冠的破坏均较严重,试验中横缝与诱导缝的先后张开分别释放了拱向端部应力与冠部应力,从而引导了裂纹开裂方向,减轻坝体破坏。通过实际震害与物理模拟的对比验证了试验结果的可靠性,显示本文的物理模拟技术有助于研究结构缝对拱坝地震破坏机理和最终失效模式的影响,可为碾压混凝土拱坝的抗震设计提供科学依据。     

长距离引调水工程PCCP设计关键技术

PCCP(预应力钢筒混凝土管)在我国引调水工程应用中越来越广泛,制管工艺与运用技术日趋成熟,但在工程设计方面的认识还有不少分歧。本文根据设计同类工程的实例,结合工程运行情况和试验资料,对管材比选方法、水力学计算、止推设计等PCCP工程设计关键技术进行了研究,得到了相应结论。研究成果可供工程设计人员参考。     

Seepage and stress analysis of anti-seepage structures constructed with different concrete materials in an RCC gravity dam

This study used the finite element method(FEM) to analyze the stress field and seepage field of a roller-compacted concrete(RCC) dam, with an upstream impervious layer constructed with different types of concrete materials, including three-graded RCC, two-graded RCC, conventional vibrated concrete(CVC), and grout-enriched vibrated RCC(GEVR), corresponding to the design schemes S1 through S4. It also evaluated the anti-seepage performance of the imperious layer in the four design schemes under the normal water level and flood-check level. Stress field analysis of a retaining section and discharge section shows that the maximum tensile stress occurs near the dam heel, the maximum compressive stress occurs near the dam toe, and the stress distributions in the four schemes can satisfy the stress control criteria. Seepage field analysis shows that the uplift pressure heads in schemes S3 and S4 descend rapidly in the anti-seepage region, and that the calculated results of daily seepage flow under the steady seepage condition in these two schemes are about 30%e50% lower than those in the other two schemes, demonstrating that CVC and GEVR show better anti-seepage performance. The results provide essential parameters such as the uplift pressure head and seepage flow for physical model tests and anti-seepage structure selection in RCC dams.