Numerical Study of Dam-Break Induced Tsunami-Like Bore with A Hump of Different Slopes

Numerical simulation of dam-break wave, as an imitation of tsunami hydraulic bore, with a hump of different slopes is performed in this paper using an in-house code, named a Constrained Interpolation Profile (CIP)-based model. The model is built on a Cartesian grid system with the Navier Stokes equations using a CIP method for the flow solver, and employs an immersed boundary method (IBM) for the treatment of solid body boundary. A more accurate interface capturing scheme, the Tangent of hyperbola for interface capturing/Slope weighting (THINC/SW) scheme, is adopted as the interface capturing method. Then, the CIP-based model is applied to simulate the dam break flow problem in a bumpy channel. Considerable attention is paid to the spilling type reflected bore, the following spilling type wave breaking, free surface profiles and water level variations over time. Computations are compared with available experimental data and other numerical results quantitatively and qualitatively. Further investigation is conducted to analyze the influence of variable slopes on the flow features of the tsunami-like bore.     

高混凝土面板堆石坝流变的三维有限元数值模拟

采用一种新的能模拟高围压条件的堆石料幂函数流变本构模型,对水布垭面板堆石坝进行了考虑堆石料流变特性的应力-应变仿真分析。结果表明,考虑堆石料流变特性后的坝体变形有明显的增加,坝体应力有所松弛。堆石体的流变特性使得面板的挠度有所增加,面板顺坡向和坝轴向拉应力极值有所增大。对于分期浇筑面板、分期蓄水的高混凝土面板堆石坝,选用合适的流变本构模型正确地模拟堆石体的流变特性,其结果可以为大坝填筑进度及面板分期浇筑时间的确定提供参考,对于正确地预测大坝的应力变形也具有重要意义。     

Flood Management Strategy for the Upper and Middle Odra River Basin: Feasibility Study of Raciborz Reservoir

The river Odra, which rises in the Czech Republic and disgorges into the Baltic, suffered an extreme flood in July 1997 which was responsible for the loss of 55 lives and over a billion dollars worth of damage in southern Poland. The return period of the flood is variously estimated between 250 and 1000 years. The paper describes the hydrological and hydraulic studies undertaken for a flood reservoir (storage capacity is approximately 180,000,000 m³) to be constructed on the River Odra just upstream the ancient town of Raciborz, on the border between Poland and Czech Republic. These studies included the hydrodynamic modelling of a 220 km stretch of the river down to the city of Wroclaw where most of the damage occurred, flood damage analysis with and without the proposed reservoir, sensitivity analysis of operating rules for Nysa reservoirs and improvement of flood control capacity of existing channels and polders. Cost-benefits analysis, environmental impact assessments and resettlement plans, in addition to the engineering studies of the dam itself, were also carried out during the project stage but have not been included in the present paper.     

植物特征与某滑坡坝形成时间和稳定性关系

植物生长受其生长环境的影响，一定的生长情况，反映了其生活环境。在环境、生物、地质等学科，通过对植物种属、生长形态等分析，可以表明其生活环境的某些特征。在地质上，马刀树的存在是滑坡存在一个典型证据，生存时间较长的树，是其生活地区的活化石，对其进行分析，可以论证地质体的稳定性，在自然风景区和国家保护区，这种方法是非常具有应用价值的。本文通过对某一保护区的滑坡坝顶部生长的树木分析，确定其形成时间，这同其它调查结果是一致的。计算分析表明滑坡坝在形成后处于稳定状态，它同植物生长特征符合。表明这种分析方法是一种简易实用的方法，对其它工程也有借鉴意义。     

Recent changes of Shandong sandy coast and in fluence of human activities

Ｒｅｃｅｎｔ　ｃｈａｎｇｅｓ　ｏｆ　Ｓｈａｎｄｏｎｇ　ｓａｎｄｙ　ｃｏａｓｔ　ａｎｄ　ｉｎ　ｆｌｅｎｃｅ　ｏｆ　ｈｕｍａｎ　ａｃｔｉｖｉｔｉｅｓTXＲｅｃｅｎｔｃｈａｎｇｅｓｏｆＳｈａｎｄｏｎｇｓａｎｄｙｃｏａｓｔａｎｄｉｎｆｌｕｅｎｃｅｏｆｈｕｍａｎ...     

锦屏一级高拱坝坝基加固效果分析

锦屏一级高拱坝复杂的坝址地质条件使基础加固处理工程巨大,主要包括左岸混凝土垫座置换、左岸传力硐、左岸f5、f8、煌斑岩脉混凝土网格置换,右岸f13、f14断层混凝土网格置换。采用非线性有限元分析方法,对坝基加固后锦屏一级水电站坝体在多种工况下的的应力、变形特性进行了计算分析,给出了坝体蓄水期的应力、位移分布及超载、降强对位移的影响结果,并与无垫座方案的相关数据进行对比,表明加固后坝体蓄水期总体变形规律明显改善,坝踵拉应力减小,坝体与坝基安全储备能力提高,满足设计要求;在应力、变形方面肯定了大规模加固措施的必要性。     

水库输水隧洞施工爆破振动对大坝安全影响监测及分析

阐述柏峰水库除险加固工程主坝输水隧洞施工爆破振动对大坝安全影响。选择有代表性的几个部位,采用原位质点振动速度测试的方法对整个施工期间爆破振动对大坝安全影响进行全过程监测与分析。对实测结果分析表明,爆破振动对大坝安全未产生明显的危害。监测成果可为工程爆破振动安全评价提供科学依据。     

小湾水电站坝肩不良地质体及工程处理

小湾水电站为大（Ⅰ）型一等工程,其大坝类型为混凝土双曲拱坝。双曲拱坝由于传力特性,其对坝肩岩体的抗滑、抗剪要求较高,小湾水电站坝肩不良地质体较为发育,因此不良地质体边界的确定及力学参数的研究显得极为重要,在工程的实际处理中,针对坝肩不良地南体设计了洞塞置换和抗剪洞,坝肩洞塞的增设增加了坝肩的稳定,提高了坝肩的安全丰裕度。     

跨孔超高密度电阻率法在球状风化花岗岩体探测中的应用

稻城古冰帽中心海子山广布粒度成分不同的由冰碛物和冲洪积物等组成的松散堆积物,给高海拔宇宙线观测站(LHAASO)规划建设带来挑战。对高坡垄岗部位5处冰碛花岗岩砾石、堰塞盆地中2处阶地冲洪积物进行现场观测和取样分析。对106块砾石采用线面集中统计,得到冰碛物砾石数量占百分比较高的砾径为0.5~2.5 m,面积2.5~7.5 m²,体积5 m³。块石形状多为长方体-厚板状,部分面接触为主。采用音频大地电磁法(AMT)等进行探测,解释得到场地冰碛体厚约30 m。对冲洪积物的含砾土和细碎屑土的2个砂砾样品用筛分法和激光粒度法进行粒度成分测定,得中值粒径d₅₀=2 mm、0.7mm,不均匀系数C_u=5.40、2.42,曲率系数C_c=0.60、0.95。这两种冲洪积物均为不良级配的土,即均粒土。这些成因和结构不同的冰碛物和冲洪积物对工程布设有不同影响,在工程实践中给予了区分利用。     

土坝震害评估模型研究

为了快速准确地对遭受地震影响的土坝工程的破坏状态进行评估,以土坝震害经验统计判断模型为基础,选取了更为合理的土坝震害影响因素,采用最小二乘法重新对土坝震害数据资料进行回归分析,得到了各震害影响因素在不同条件下的回归系数取值,从而建立了一个改进的土坝震害经验统计判断模型。与原模型相比,改进模型既剔除了不合理的震害影响因子,同时又使回归模型的预测准确度得到提高,其相关系数为0.908,标准差为0.459,均比原模型要好。采用两种模型对汶川地震中遭到破坏的47座土坝进行震害评估,并与实际震害进行了对比分析,初步验证了改进模型的可靠性