水泥砼路面板底脱空对沥青加铺层反射裂缝的影响分析

采用三维有限元分析方法，计算分析了具有接缝的旧水泥混凝上路面上沥青加铺层在行车简载作用下应力随板底脱空的变化情况，从理论上深入研究了不同板底脱空对沥青加铺层反射裂缝的影响，阐述了板底脱空对沥青加铺层荷载应力的影响。     

水泥混凝土路面板下脱空的危害

通过对多处水泥混凝土路面板下脱空形态的试验研究 ,获得脱空区的形态分布规律 ,并据此对不同车辆荷载作用下板体内应力变化进行解析求解和使用寿命计算。结果表明 ,水泥混凝土路面板下脱空、超载车辆和重载车辆是造成水泥混凝土路面板早期断裂的重要因素     

关于水泥混凝土板下脱空评定标准的探讨

分析了水泥混凝土路面出现的板底脱空现象，并利用Westergaard理论，对板下脱空的评定标准进行了探讨。以黑龙江省某公路的观测数据为依据，通过威氏理论分析，从而得到了一种方便而实用的判定板底脱空的评定标准，并利用相同路面结构的公路的观测数据验证此标准的适用性。     

膜下滴灌施肥对樱桃产量品质和土壤肥力的影响

为寻求膜下滴灌施肥条件下果树栽培的最佳水肥调控阈值,以樱桃为试验材料,灌水量和施肥量各设3个水平(即设计灌溉定额的70%、85%和100%及推荐滴灌施肥量的60%、80%和100%),传统畦灌冲施为对照,为寻求膜下滴灌施肥条件下樱桃栽培的最佳水肥调控阈值进行了研究。结果表明:灌水量、施肥量和水肥交互作用对樱桃的产量品质和土壤养分含量等指标有不同程度的影响。相比传统畦灌冲施方式,膜下合理滴灌施肥能得到更佳的产量品质和土壤肥力,能有效提高樱桃树的水分利用效率和肥料偏生产力。其中,最佳水肥组合是中水高肥(W_2F_3),其产量(3 174.61kg/hm~2)、纵径(23.15mm)、可溶性总糖含量(17.82%)和水分利用效率(9.69kg/kg)达到最高,可滴定酸较低(0.41%),主要吸水吸肥土层(20~40cm)的全氮含量最高,其他品质、速效养分和有机质等指标也处较高水平。该研究为果园拟定高效高产的滴灌施肥制度提供了数据支撑。     

压浆技术在道桥工程中的应用

水泥砼底脱空,对路面破该严重,其维修和养护工作难度大,耗资多。而利用板底压浆技术处治此类病害时技术效果和经济效果较好。     

Structural Design of the Multi_Purpose Building for the Public Security Bureau,Xin Xiang City Henan Province

This paper introduces the methods of reducing and controlling differential settlement by changing the length and load_bearing capacity of the piles,and other means,rather than setting settlement gaps between the main building and the podium structure.By using these methods,the size of differential settlement observed is only 1mm.Because of the building with a tower 45m high,the earthquake magnification factor is taken as 3 with considering whiplash effect.     

Finite Difference Analysis on Cantilever Slab Model with Void beneath the Cement Concrete Slab Corner

The advantages and shortcomings of traditional method and Finite Difference Method (FDM) for the calculation of cantilever slab model with void beneath cement concrete slab corner and analysis on the results were carried out. The traditional method assumes that the cement concrete slab with void below was a cantilever slab with constant sections. The influence of loading eccentricity was not considered while more than two wheel loads were exerted on the concrete pavement, which can be overcome by using Finite Difference Method. With FDM, the stress and displacement distributions of any parts of the cement concrete slab can be easily achieved. The results indicate that when the concrete slab with void beneath the slab corner was assumed to be a cantilever slab, regardless of calculation by traditional method or by FDM, the cement concrete pavement will be destroyed even under the condition of minimum traffic grade. The fatigue stress and road deflection obtained by FDM are bigger than that obtained by the traditional formula, so bigger safety factor should be employed in the road design.