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51.
随着社会化进程的推进,顶管法在各类城市地下管线的施工中得到广泛应用。超浅层顶管施工。绝大多数是在已建道路下进行的,施工时,易发生地表沉降,且沉降量很大,易破坏路面。为此,超浅层顶管施工对周围环境的影响已引起人们足够的重视,其施工及控制技术是目前迫切需要掌握的。利用有限差分软件FLAC3D对顶管施工过程中地表沉降进行模拟,旨在了解超浅层顶管施工引起的力学效应。对超浅层顶管施工引起的地表沉降作出预测,为采取措施减小地表沉降提供依据。 相似文献
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Influence of underground space development mode on the groundwater flow field in Xiong’an new area
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Yi-hang Gao Jun-hui Shen Lin Chen Xiao Li Shuang Jin Zhen Ma Qing-hua Meng 《地下水科学与工程》2023,11(1):68-80
The degree and scale of underground space development are growing with the continuous advancement of urbanization in China. The lack of research on the change of the groundwater flow field before and after the development of underground space has led to various problems in the process of underground space development and operation. This paper took the key development zone of the Xiong’an New Area as the study area, and used the Groundwater modeling system software (GMS) to analyse the influence on the groundwater flow field under the point, line, and surface development modes. The main results showed that the underground space development would lead to the expansion and deepening of the cone of depression in the aquifer. The groundwater level on the upstream face of the underground structure would rise, while the water level on the downstream face would drop. The “line” concurrent development has the least impact on the groundwater flow field, and the maximum rise of water level on the upstream side of the underground structure is expected to be approximately 3.05 m. The “surface” development has the greatest impact on the groundwater flow field, and the maximum rise of water level is expected to be 7.17 m. 相似文献
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基于动力学仿真软件AUTODYN,对椭圆双极线性聚能药柱(EBLSC)进行了数值模拟。采用二维面对称计算方法,花岗岩岩体,空气夹层不耦合装药条件,研究了EBLSC结构及不耦合系数对光面爆破效果的影响,并建立有效体积功模型以评价爆破效果。结果表明,炮孔连线方向和垂直方向上的比冲量相近,偏差<10%,故总能量沿周向近似均匀分布,但炮孔连线方向产生明显侵彻裂隙,且粉碎圈厚度和腔体扩张程度要小得多,表明该装药结构能够明显提高炸药能量的利用率和爆破效果;随着不耦合系数增大,炮孔连线方向上的损耗体积功先减小后增大,存在最大有效功。利用曲线拟合,得到最优不耦合系数约3.62,与相关文献的试验结果相近。 相似文献
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钢围堰内混凝土拆除爆破工程较为鲜见 ,文章介绍了该工程所选取的爆破诸参数以及所采用的施工工艺 ,可供同行参考 相似文献
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At present, most calculation results regarding foundation pit dewatering are ideal values, making construction resources prone to being wasted. In order to optimize the traditional pipe well design of large wells, the linear programming solution module in Excel is used, with the total water inflow taken as the objective function, the water level drawdown used as the constraint and test condition, and a station project on the Chengdu Metro Line 7 serving as the subject of this study. The total water inflow of the traditional pipe well design is optimized by the simplex method, producing a total water inflow of 4 040.65 m~3/d, which, compared with 4 829.79 m~3/d, the total water inflow calculated by means of the traditional design optimization method, engenders a reduction of roughly 16% per day. The feasibility of the optimization methodology is verified by the drawdown constraint, which reveals the decrease of construction costs and the diminution of the influence that the lowered groundwater level has on the surroundings of the metro station. Finally, references are provided as to optimizing the dewatering designs for other metro stations in similar engineering and hydrogeological conditions. 相似文献
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J.C. Jhanwar A.K. Cakraborty H.N. Anireddy J.L. Jethwa 《Geotechnical and Geological Engineering》1999,17(1):37-57
In blasting with air decks, repeated oscillation of shock waves within the air gap increases the time over which it acts on the surrounding rock mass by a factor at between 2 and 5. The ultimate effect lies in increasing the crack network in the surrounding rock and reducing the burden movement. Trials of air deck blasting in the structurally unfavourable footwall side of an open pit manganese mine has resulted in substantial improvements in fragmentation and blast economics. Better fragmentation resulted in improved shovel loading efficiency by 50–60%. Secondary blasting was almost eliminated. Use of ANFO explosive with this technique reduced explosive cost by 31.6%. Other benefits included reductions in overbreak, throw and ground vibration of the order of 60–70, 65–85 and 44% respectively. This paper reviews the theory of air deck blasting and describes in detail the air deck blast trials conducted in a manganese open pit mine in India. The blast performance data have been analysed to evaluate the benefits of air decking over conventional blasting. 相似文献
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