ASE复合桩技术设计及试验研究

针对吹填淤泥的超软土工程性质,提出了ASE桩的概念,即沉管投入复合材料再原位扩径搅拌的施工技术。以固化细料+骨架粗料为超软土提供基本强度及骨架支撑的原理,参考搅拌桩与CFG桩的施工工艺,制作专用双塔型施工设备,尝试形成一种新的施工工艺。进行了现场初步试验,固化细料与骨架粗料的配合比较理想时,可形成较为理想的桩体。成桩质量主要受固化细料影响,骨架粗料的效果发挥需要依赖一定配合比基础的固化细料。先沉管投料再扩径搅拌的工艺是可行的,环刀型叶片能够实现扩径的效果,且双向扩径搅拌的效果要好于单向扩径搅拌的效果。ASE桩的设计计算方法及理论还需做进一步研究,可参考CFG桩与搅拌桩的相关理论开展工作,为地基处理技术的发展提供了新的思路。     

Morphology and stratigraphy of the late Quaternary lower Brazos valley: Implications for paleo-climate, discharge and sediment delivery

A shallow coring and geophysical logging program has recorded the sedimentary fill of the Brazos River valley in the Texas Gulf Coastal Plain. Thermoluminescence dates together with new and recalibrated published radiocarbon dates show the valley fill to include extensive, sandy, buried falling stage and lowstand Oxygen Isotope Stage (OIS) 3 and 2 deposits. These alluvial deposits are punctuated by numerous paleosoil horizons that record alternating periods of cutting, bypass and accumulation. Maximum valley incision and two periods of terrace formation preceded marine lowstand conditions, suggesting significant discordance between preserved fluvial and classical marine system tracts. The latest Pleistocene incision and fill history appears related to cycles of increased discharge and incision, followed by system equilibration and terrace formation. Analysis of the Brazos River incised valley and its contained paleochannels indicates that latest Pleistocene mean annual discharge was as much as four times greater than that of today. This magnitude of discharge in the Brazos would require a two-fold increase in precipitation across the drainage basin. Such an increase is comparable to the present day measured positive El Niño winter precipitation anomaly across the region. Paleochannel geometries and the stratigraphic and sedimentologic data from this investigation support the hypothesis that periods of high-amplitude, El Niño-like climatic perturbations characterized the late Quaternary climate of the south-central and southwestern U.S. This period of high discharge coincides, at least in part, with late OIS 3 progradation of the Brazos delta to the shelf margin, OIS 3 and 2 valley incision across the Texas shelf, and concomitant sand bypass to intraslope basins beyond the shelf edge.     

Emplaced Geotechnical Characteristics of Hydraulic Fills in a Number of Australian Mines

Hydraulic fills used in Australian mines have similar grain size distributions whilst having quite different specific gravity values, typically in the range of 2.7–4.4. When produced and distributed in slurry at 65–75% by solid content, they settle to produce fills with similar geotechnical characteristics. The fills under investigation have been found to settle, in the laboratory, to a dry density of about 0.56 × specific gravity, a saturation water content of about 17–34%, and a porosity of 37–49%. A quick estimate of the optimum water content that gives the minimum porosity may be obtained by locating the intersection of the saturation curve and minimum porosity line, which may simply be done on a water content vs. porosity plot. However, transportability of the slurry requires it to be mixed at water content substantially greater than the optimum water content. As the tailings settle out of suspension, they settle to relative density of 50–80%. This paper shows that the current empirical relationships relating relative density and N-value to friction angle for sands will significantly underestimate the friction angle of the hydraulic fills. Based on limited experimental data, a unique relationship between relative density and friction angle is proposed for hydraulic fills placed in some Australian mines.     

二维地震勘探变观量板图及其应用

在以炸药为震源的二维地震勘探野外资料采集施工中,需要避开各种不能钻井放炮的障碍物,根据勘查区设计任务书的施工参数,可以画出变观量板图。变观量板图具有快速变观的作用,野外所遇到的不同距离的障碍物可以通过变观避开,给施工提供方便,变观量板图具有实际应用价值。     

组合结构支挡体系在杂填土层深基坑支护中的应用

在古城区建筑地基上部,广泛赋存以炉灰渣为主要成分的杂填土,其厚度不一。随着城市化进程的迅猛发展,旧城改造对高层建筑地下空间的充分利用提出了更高要求,特别是在周围恶劣环境条件下开挖空间,从理论、实践上深入研究闹市区杂填土深基坑,采用何种经济技术合理的支护方案问题十分突出。但各种深基坑支护方法都有其局限性,岩土工程师在确定方案时必须充分考虑当地工程地质条件、建筑物基坑特点,选择组合支护技术方法,方可达到事半功倍之目的。通过成功支护某杂填土深基坑工程实例,详尽阐述了杂填土的工程特性、锚拉钢板桩挡墙、土钉挡墙的基本参数选取、设计计算,可为类似岩土工程条件下的基坑支护方案选型和设计提供借鉴及参考。     

江苏连云港地区吹填土室内沉积试验研究

近年来，随着港口建设的飞速发展，将疏浚出来的淤泥用来填海造陆，已成为沿海城市缓解土地资源紧张的有效途径。由于吹填淤泥性质十分复杂，并且需要很长时间的自然沉积固结，待表面形成硬壳后方可加固处理。因此，对吹填土沉积规律和自重固结机理的研究显得尤为重要。本文以连云港地区吹填土为主要研究对象，通过室内沉积试验，对吹填土在静水条件下的沉积规律及固结特性做了系统分析和研究，并对沉积后的吹填土进行了微观结构定量分析，获得了孔隙直径、丰度、平面形态、定向频率、定向分维数等重要参数，该成果为吹填土地基加固提供了有力的参考依据，对于工程实践具有重要意义。     

Hydrogeological evolution of the Luni river basin,Rajasthan, western India: A review

The Luni river basin has been evolved as a result of typical hydrogeomorphic processes of arid zone, operating under the influence of active tectonic lineaments. A detailed analysis of stream morphology in relation to geology and lineaments carried out on selected windows indicated the morphological control of the streams while flowing over the lineaments from the eastern to the western part of the basin. Typical valley fills indicated by dark green tone on digitally processed images and the pediments showing greenish white tone appear in sharp contrast and indicate respectively the graben and horst structures. A detailed identification of lineaments for the georesources and geological evaluation has been carried out. Earlier analysis carried out on Bouguer anomalies correlate with graben and horst structures in the subsurface. Quaternary sequences have been dated from 80 ka to 3 ka indicating a range of fluvial to aeolian deposits reflecting prevailing climatic conditions. However, the changes in sediment type from coarse and mixed of all size grades to fine in a vertical litho-column warrant further studies on fine resolution stratigraphy and high resolution stratigraphy for understanding climatic variations in the region     

数字河道测量系统的研究与开发

河道测量作为河流治理和开发的基础，其技术发展和研究已引起有关部门的高度重视，在河流治理开发和水资源利用中占有极其重要的地位。文中介绍了GPS导航定位数字河道测量系统RISS的开发背景和意义，简述了该系统的总体结构、功能、特点和应用。     

Tectonic controls on spatio-temporal development of depositional systems and generation of fining-upward basin fills in a strike-slip setting: Kyokpori Formation (Cretaceous), south-west Korea

Abstract The Kyokpori Formation (Cretaceous), south‐west Korea, represents a small‐scale lacustrine strike‐slip basin and consists of an ≈ 290 m thick siliciclastic succession with abundant volcaniclasts. The succession can be organized into eight facies associations representing distinctive depositional environments: (I) subaqueous talus; (II) delta plain; (III) steep‐gradient large‐scale delta slope; (IV) base of delta slope to prodelta; (V) small‐scale nested Gilbert‐type delta; (VI) small‐scale delta‐lobe system; (VII) subaqueous fan; and (VIII) basin plain. Facies associations I, III and IV together constitute a large‐scale steep‐sloped delta system. Correlation of the sedimentary succession indicates that the formation comprises two depositional sequences: the lower coarsening‐ to fining‐upward succession (up to 215 m thick) and the upper fining‐upward succession (up to 75 m thick). Based on facies distribution, architecture and correlation of depositional sequences, three stages of basin evolution are reconstructed. Stage 1 is represented by thick coarse‐grained deposits in the lower succession that form subaqueous breccia talus and steep‐sloped gravelly delta systems along the northern and southern basin margins, respectively, and a sandy subaqueous fan system inside the basin, abutting against a basement high. This asymmetric facies distribution suggests a half‐graben structure for the basin, and the thick accumulation of coarse‐grained deposits most likely reflects rapid subsidence of the basin floor during the transtensional opening of the basin. Stage 2 is marked by sandy black shale deposits in the upper part of the lower succession. The black shale is readily correlated across the basin margins, indicating a basinwide transgression probably resulting from large‐scale dip slip suppressing the lateral slip component on basin‐bounding faults. Stage 3 is characterized by gravelly delta‐lobe deposits in the upper succession that are smaller in dimension and located more basinward than the deposits of marginal systems of the lower succession. This lakeward shift of depocentre suggests a loss of accommodation in the basin margins and quiescence of fault movements. This basin evolution model suggests that the rate of dip‐slip displacement on basin‐margin faults can be regarded as the prime control for determining stacking patterns of such basin fills. The resultant basinwide fining‐upward sequences deviate from the coarsening‐upward cycles of other transtensional basins and reveal the variety of stratigraphic architecture in strike‐slip basins controlled by the changes in relative sense and magnitude of fault movements at the basin margins.     

灰土碎石振动挤密桩在杂填土地区的地基处理施工方法和作用

在新近杂填土上建厂，因杂填土松散、厚度大、基岩埋深大，若采用基岩作天然地基即用人工挖孔桩或机械成孔灌注桩，则很不经济，施工也存在安全隐患，易坍孔，且工期长。经过比较，采用灰土碎石挤密桩对杂填土进行处理后，作复合地基，施工易于操作并极大的缩短了工期，取得了良好的效果。