SOIL DAMPING FORMULATION IN NONLINEAR TIME DOMAIN SITE RESPONSE ANALYSIS

Nonlinear time domain site response analysis is used to capture the soil hysteretic response and nonlinearity due to medium and large ground motions. Soil damping is captured primarily through the hysteretic energy dissipating response. Viscous damp-ing, using the Rayleigh damping formulation, is often added to represent damping at very small strains where many soil models are primarily linear. The Rayleigh damping formulation results in frequency dependent damping, in contrast to experiments that show that the damping of soil is mostly frequency independent. Artificially high damp-ing is introduced outside a limited frequency range that filters high frequency ground motion. The extended Rayleigh damping formulation is introduced to reduce the over-damping at high frequencies. The formulation reduces the filtering of high frequency motion content when examining the motion Fourier spectrum. With appropriate choice of frequency range, both formulations provide a similar response when represented by the 5% damped elastic response spectrum.

The proposed formulations used in non-linear site response analysis show that the equivalent linear frequency domain solution commonly used to approximate non-linear site response underestimates surface ground motion within a period range relevant to engineering applications. A new guideline is provided for the use of the proposed formulations in non-linear site response analysis.     

考古学次生堆积的研究与探索

一、问题的提出 随着当代考古学的目标从器物描述扩展到对人类行为的信息提炼,对考古遗址中文化堆积改造和遗址形成过程的了解,便成为田野工作的一项重要方面。虽然,对过去社会文化和人类活动的了解取决于考古学家对遗址的仔细发掘和采样,但是发掘和采样在多大程度上反映了历史的真实面貌,则是一个很大的未知数。因为,考古遗址从形成开始,不但受到人类活动的改造,而且在使用时和废弃后的漫长岁月里,还会被堆积后的自然和人类动力破坏得面目全非。所以,如果要科学地认识考古学文化,仔细分辨人类和自然对考古遗址的改造和扰动就必…     

郑州市银基商贸城商代外夯土墙基发掘简报

图一 郑州市银基商贸城商代外夯土墙基发掘位置图１９９４年１１月,郑州市文物工作队（现郑州市文物考古研究所）在位于郑州市一马路以东、西三马路以北的银基商贸城,配合基建进行了考古发掘。（图一）发掘工作从１１月２３日开始,至１２月２４日结束。共发掘探方４个,发掘面积７０６平方米。（图二）清理商代外夯土墙基一段和数个商代灰坑,出土一批商代陶、石器,取得了较为丰富的成果。现将此次发掘的主要收获简报如下。一、地层堆积与夯土墙基１地层堆积发掘者进入银基商贸城工地前,施工现场已被下挖１米。所布探方大致与夯土墙…     

河南焦作市府城遗址发掘简报

府城遗址位于焦作市西南府城村西北部的台地之上,距市中心约10公里,北距太行山约15公里,南距沁河约20公里。遗址北部自西向东有一条小河流过,南部被严重破坏,仅剩北中部。遗址平面呈方形,南北长约300米,东西宽约310米,是河南省重点文物保护单位。(图一)1992年,焦作市...     

Displacement Ductility Limits for Pile Foundations in Cohesionless Soils

The displacement ductility limit for seismic design of concrete piles is determined for the range of cohesionless soils expected in practice. The curvature ductility capacity associated with specified performance limit states, namely, the “serviceability” and “damage-control” limits, is determined based on the current provisions for confining steel. An analytical model is applied to assess the displacement ductility factor at the specified curvature ductility level. The investigated parameters include the soil stiffness, pile diameter, longitudinal reinforcement ratio, axial force level, and pile above-ground height. A set of design displacement ductility factors is recommended and verified to ensure the satisfactory seismic performance.     

Beyond the identification of formation processes: Behavioral inference based on traces left by cultural formation processes

Formation processes are generally considered as a negative factor for behavioral inference in archaeology. The concept of formation processes, however, can potentially be far more useful for behavioral inference in archaeology than simply identifying spurious variability in the archaeological record. Physical traces left by cultural formation processes convey a certain kind of behavioral information which may not be otherwise available. Variables related to site occupation, such as the occupation span, the number of occupation episodes, and the location of activities, can be inferred from characteristics of refuse deposits, or refuse structure.     

Fruits in foundation deposits of two temples

Foundation deposits underneath the walls of two temples near Semna, Sudan (c. 1500-1480 BC), included dried plant material. Five fruit species are represented: Vitis vinifera (grape), Ficus carica (fig), Citrullus vulgaris (water melon), Phoenix dactylifera (date) and Ziziphus spina-christi. Of particular interest are the remains of tubers of Cyperus esculentus. The plants mentioned above are known as funeral gifts in Egyptian tombs.     

唐淮西节度使相关问题考论

淮西节度使在安史之乱初期设立时,与其他内地藩镇并没有大的区别,其设置的最主要目的,是为了平定中原地区的战乱,而且也确实发挥了一定的作用。之后,它经历了复杂的变迁,区域不断缩小,直至剩下三州之地。但是它与中央对抗的趋势却更加明显,其主要原因在于藩镇制度下它与中央对地方利益的争夺,区域内部的胡化只是一个浅层的诱因。这一地区的经济、社会基础及区位条件也为它提供了支持。唐王朝以藩镇体制之外的手段,使用武力将它平定,迎来了自己短暂的"中兴",却无法避免之后的更加衰落乃至灭亡。     

The ARchaeological Organic residues Literature Database (AROLD): Construction of a tool for reviewing and querying published lipid data in organic residue analysis

The first attempts to identify amorphous organic substances in archaeology date to the end of the 19th century and the beginning of the 20th century. The 1960s saw the development of infrared spectrometry, and then separative and mass spectrometry analyses were implemented in the 1980s. But it is only since the 1990s that extended and systematic research programmes were devoted to these substances. The number of publications has not stopped growing and is becoming exponential. To get an overview of the lipid studies in archaeology, we conceived the ARchaeological Organic residues Literature Database (AROLD) as a first structured and collaborative research tool. This paper describes the challenges of setting up such a database, details its architecture, presents the choices involved in its implementation, and discusses the possibilities of sharing and evolving this tool.     

Luminescence dating of anthropogenic deposits from Tall Zarʿa in the Jordan Valley

This study uses quartz-based optically stimulated luminescence dating to determine when a massive fortification wall (W11186) was constructed in the archaeological site of Tall Zarʿa in the Jordan Valley. A total of 11 samples of sediments were taken from a trench on the north side of the wall (extramuros). The extracted quartz grains had good luminescence characteristics and were identified as well bleached by comparison with feldspar infrared-stimulated luminescence (IRSL) ages. The optical ages showed that the deposition against the wall occurred in two different periods. The first was around 3.20 ± 0.07 ka ago (Iron Age), and the second was around 2.28 ± 0.08 ka (Hellenistic period). Human activity was evident because of the intermixing of cultural material with the presumed naturally deposited units.