内-宜高速公路K96+800～K99+380路基病害成因分析及防治方法探讨

内宜高速公路K96 +80 0～K99+380地处四川盆地南部构造剥蚀丘陵区 ,穿越多个山丘和谷地 ,造成该段路基有人工填筑土、第四系淤泥质土等不良地质体 ,因而形成该段路基病害为过量沉降及沉降差和侧向挤出及局部坍滑两种类型。造成这种病害的原因是该路段局部填筑区地势低洼 ,自然排水困难 ,填筑土高度大、宽度大 ,未能真正压实固结。淤泥质土天然孔隙比大 ,为高压缩性土 ,且厚度大、埋深大。二者抗剪强度低 ,承载力低 ,是产生路基过量沉降及沉降差的主要原因。除上述原因外 ,由于高速公路加荷速率快 (路堤施工速率快 ) ,路堤接近或达到极限高度 ,附加剪应力高、荷载宽度大等是造成路基侧向挤出和局部坍滑的主要原因。对以上的两种路基病害治理采取压浆、旋喷及粉喷桩相结合 ,上部路堤填筑土体采取压浆加固 ,下部淤泥质土等软弱土采取深层搅拌桩 (旋喷及粉喷桩 )加固。二者结合还可对治理区产生群桩效应 ,同时提高地基土的密实度 ,防治路基侧向塑性挤出和坍滑。

Review on Dating Methods:Numerical Dating in the Quaternary Geology of High Asia

Over the past few years, OSL and TCN datings of glacial material from High Asia have come into fashion. To this day, however, these techniques do not permit safe calibration. The intensity of the cosmic ray flux is being modulated by the solar and terrestrial magnetic fields and their secular fluctuations in the past. So far, these variations cannot be converted into the respective local TCN production rates for High Asia. We have reason to believe that the ages that are being calculated despite these uneertainties are generally overestimated. This assessment is supported by eonventional radiocarbon dates and above＂ all by the glacial chronology developed independently on the basis of the Quaternary geological method. The strongly emerging evidence for a much more extensive LGM glaciation of High Asia is, however, either being ignored or rejected by many authors, solely on the basis of the above-mentioned uncalibrated datings. This self-conceit based on the ＂dating fallacy＂, as we call it, should be avoided since it goes decidedly against the standards of the scientific method established in Quaternary geology and makes a fundamental scientific discussion impossible.

PROGRESS IN QUATERNARY AEOLIAN ENVIRONMENT RESEARCH

Quaternary aeolian environment researches were mainly conducted by analyzing the information carriers, extracting valuable evidences about aeolian environment changes, so to presume and reconstruct paleoenvironments. This paper formulated progress in Quaternary aeolian environment research using dune-morphological records, sedimentological records and bio-fossils records, as well as advances about chronology; presented that people should pay more attention to further synthetic study of multi-types of records including dune morphology, size, formation time, sediment supply, and their relations with wind regime in future, especially the research on dating method.

Genetic analysis of land subsidence in Anshan

Land subsidence is a complex geological phenomenon which is concerned by the researchers at home and abroad. In this paper,the observation data from Anshan Second Order Leveling during 1987-[KG-*7]-1994,combined with the area of environmental engineering geology and geological conditions analysis shows that land subsidence in Anshan City is closely related to active tectonics,Quaternary strata and groundwater exploitation.

Division of Buried Late Quaternary Strata of the Fuzhou Basin

Based on detailed logging of fourteen drill holes, combined with the results of other researchers, the preliminary summarization on sedimentary characteristics of the late Pleistocene of the Fuzhou basin is done. The deposition of Fuzhou basin began from about 56.5ka BP and the sediments are composed of gravel, sand, clay and silt, which show a depositional sequence with granularity becoming smaller from the lower to the upper and a big lateral variation of lithology. There are three silt layers in late Quaternary strata of Fuzhou basin. The first and second layers were developed during the middle and late Holocene, the deposition time is about 7.86ka BP to 1.44 ka BP and they are the results of ＂Changle Transgression＂. The third was developed during the late of late Pleistocene and the deposition time is from 44ka BP to 20ka BP and it is the result of ＂Fuzhou Transgression＂. The buried late Quaternary sediments in Fuzhou basin can be divided into upper Pleistocene series and Holocene series, which include four formations from old to new. They are the Longhai formation （ Q3p 1）, Dongshan formation （Qhd）, Changle formation （Qhc） and Jiangtian formation （Qhj）, respectively. The Longhai formation can be divided into three members and belongs to the Pleistocene series, other three formations belong to the Holocene series.

Spatial Discrimination of Complex, Low-Relief Quaternary Siliciclastic Strata Using Airborne Lidar and Near-Surface Geophysics： An Example from the Texas Coastal Plain, USA

Depositional units preserved on coastal plains worldwide control lithologic distribution in the shallow subsurface that is critical to infrastructure design and construction, and are also an important repository of information about the large-scale climate change that has occurred during many Quaternary glacial-interglacial cycles, The lateral and vertical lithologic and stratigraphic complexity of these depositional units and their response to climatic and sea-level change are poorly understood, making it difficult to pre-dict lithologic distribution and to place historical and future climate and sea-level change within a nat-ural geologic context, Mapping Quaternary siliciclastic depositional units on low-relief coastal plains traditionally has been based on their expression in aerial photographs and low-resolution topographic maps, Accuracy and detail have been hindered by low relief and lack of exposure, High-resolution air- borne lidar surveys, along with surface and borehole geophysical measurements, are being used to iden-tify subtle lateral and vertical boundaries of lithologic units on the Texas Coastal Plain within Quaternary strata, Ground and borehole conductivity measurements discriminate sandy barrier island and fluvial and deltaic channel deposits from muddy floodplain, delta-plain, and estuarine deposits, Borehole conductiv- ity and natural gamma logs similarly distinguish distinct lithologic units in the subsurface and identify erosional unconformities that likely separate units deposited during different glacial-interglacial stages, High-resolution digital elevation models obtained from airborne lidar surveys reveal previously unrecog- nized topographic detail that aids identification of surface features such as sandy channels, clay-rich interchannel deposits, and accretionary features on Pleistocene barrier islands, An optimal approach to identify lithologic and stratigraphic distribution in low-relief coastal-plain environments employs ① an initial lidar survey to produce a detailed elevation model; ② selective surface sampling and geophysical measurements based on preliminary mapping derived from lidar data and aerial imagery; and ③ borehole sampling, logging, and analysis at key sites selected after lidar and surface measure- ments are complete,

First principles study on electronic structure and optical properties of quaternary arsenide oxides YZnAsO and LaZnAsO

The electronic structure and optical properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were studied using density-functional theory(DFT) within generalized gradient approximation(GGA).The band structure along the higher symmetry axes in the Brillouin zone,the density of states(DOS) and the partial density of states(PDOS) were presented.The calculated energy band structures show that both YZnAsO and LaZnAsO are indirect gap semiconductors with band gap of 1.173 1 eV and 1.166 5 eV,respectively.The DOS and PDOS show the hybridization of Y-O/La-O atom orbits and Zn-As atom orbits.The dielectric function,reflectivity,absorption coefficient,refractive index,electron energy-loss function and optical conductivity were presented in an energy range from 0 to 25 eV for discussing the optical properties of YZnAsO and LaZnAsO.

Geological Structure and Quaternary Activity of the Zhangjiakou Fault, Northern China

Based on detailed field investigations, this paper describes the geometrical characteristics and tectonic activities of the Zhangjiakou fault at the northwest of Beijing. This fault strikes mainly northwest to west, short parts of which strike near east to west, dipping north, and extends over a length of 70km. It is a major geological and geomorphologicai margin, controlling the neotectonic movement in this region. On the south side of the Zhangjiakou fault are the Late Quaternary unconsolidated deposits, forming basins; while on the other side are Mesozoic volcano debris and Pre-Mesozoic metamorphic rocks, forming lower mountains and hills. The Zhangjiakou fault consists mainly of high-angle inverse strike-slip fault and partially of normal strike-slip fault. Among these, the north-dipping NW-NWW-trending secondary faults, constituting the main fracture of the fault, have inverse characteristics; those near the EW-trending secondary faults are links of the former faults, with a smaller length and normal faulting characteristics. Thus, the Zhangjiakou fault is a north-dipping inverse and partially south-dipping normal strike-slip fault. The Zhangjiakou fault has been continuously active since the Quaternary. With the exception of the western end extension, which has been active since the late Pleistocene, the main part of the fault has been active since the Holocene. The central main segment of the Zhangjiakou fault is more active. Since the mid-late period of the late Pleistocene, the average vertical slip rate of a single fault has been over 0. 07mm/a - 0. 30mm/a. The Zhangjiakou fault has multi-slip surfaces, and the total vertical slip rate reaches 1.33mm/a, estimated from the Qingshuihe river terraces and the relevant drilling data.

Research of the Late Quaternary Recent Activity of the Middle Segment of Kouquan Fault

Systematic research of the characteristics of late Quaternary activity of the middle part of Kouquan fault has been done through conducting 1∶50000 geologic mapping combining with remote sensing interpretation of spot imaging, field validating and chronology research of the research area. Studies suggest that the middle part of Kouquan fault has had strong activity since the late Quaternary which controls the tectonic evolvement of the nearby mountains and Datong basin. The recent activity of this fault has faulted the sandy gravel layers of T1 terrace and the lower part of dark loessial soils over the terrace on the north of Chanfang village. The maximum vertical displacement is over 3m in the area between Xiaoyukou village and Louzikou village, and to the south of Dayukou village and the north of Emaokou village, the displacement decreases to 0.5m and 0.25m respectively. Based on the recent faulted landforms and combined with dating, we determined the age of recent activity of the fault in the research area to be between 7.71ka B.P. to 3.00 ka B.P. Discussions are made on this in combination with previous research.