The morphological changes in isolated bubbles in gassy silt play a critical role in the microscopic structures between soil particles and bubbles and macroscopic physical properties.Based on X-ray CT scanning experiments under various vertical loads（four levels）,self-designed acoustic macro experiments,and a series of formula revisions to the macro-air-bearing silt sound-velocity prediction model,this paper discusses the macro-and micro-scale features of gassy silts from the Yellow River Delta.The samples consisted of different proportions of silt from the Yellow River Delta and porous media,and they were used to form two types of aerosol silts with initial gas contents of 4.23% and 7.67%.The results show that the air bubble content and external load considerably affect the microstructural parameters and acoustic behavior of gassy silt in the Yellow River Delta.The macroscopic sound velocity showed a linear positive correlation with vertical load and relation to microstructural parameters in varying manners and degrees.Based on the traditional Biot-Stoll acoustic model,the gas-phase medium coefficient was introduced for the proper calculation and prediction of the sound velocity of air-bearing silt.The errors of the overall prediction varied between 5.6% and 9.6%.

This article focuses on the effect of freeze–thaw cycling on a cement-based early-strength anchor material, the compressive strength of which at 24 h is 14 times that of ordinary cement, and the compressive strength at 7 h is twice that of ordinary cement. The setting time required to achieve the expected strength is 1/7 of that of ordinary cement. Through indoor freeze–thaw cycling tests, the appearance changes, quality loss, strength loss, and microstructure changes in the early-strength anchor after 0, 5, 15, 25, 50, 75, and 100 cycles were studied, revealing the evolution of the mechanical properties and micromechanisms of the cement-based early-strength anchor material under freeze–thaw cycling conditions. The sample freeze–thaw failure criteria were determined, evaluation indicators reflecting the degree of damage were defined, and their relationships with the number of freeze–thaw cycles were fitted to assess the durability of the cement-based early-strength anchor material under freeze–thaw environments. This provides a theoretical reference for further improvements in material properties and adaption to different environments.

Fine-grained silt is widely distributed in the Huanghe River Delta（HRD） in China, and the sedimentary structure is complex, meaning that the clay content in the silt is variable. The piezocone penetration test（CPTu） is the most widely approved in situ test method. It can be used to invert soil properties and interpret soil behavior. To analyse the strength properties of surface sediments in the HRD, this paper evaluated the friction angle and its inversion formula through the CPTu penetration test and monotonic simple shear test and other soil unit experiments. The evaluation showed that the empirical formula proposed by Kulhawy and Mayne had better prediction and inversion effect. The HRD silts with clay contents of 9.2%, 21.4% and 30.3% were selected as samples for the CPTu variable rate penetration test. The results show as follows.（1） The effects of the clay content on the tip resistance and the pore pressure of silt under different penetration rates were summarized. The tip resistance Q t is strongly dependent on the clay content of the silt, the B q value of the silt tends to 0 and is not significantly affected by the change of the CPTu penetration rate.（2） Five soil behavior type classification charts and three soil behavior type indexes based on CPTu data were evaluated. The results show that the soil behavior type classification chart based on soil behavior type index ISBT, the Robertson 2010 behavior type classification chart are more suitable for the silty soil in the HRD.

Understanding the comprehensive impact of phosphorus sources on microalgae growth process is an essential precondition for microalgae cultivation. In this study, the combination of inorganic phosphorus (K2HPO4 and Na5P3O10) and organic phosphorus (ATP and G6P) on microalgae biochemical metabolism and phosphorus transformation with wastewater was clarified. Both inorganic phosphorus (IP) and organic phosphorus (OP) could be absorbed and utilized by Chlorella pyrenoidosa under mixotrophic condition. The maximum dry cell weight was obtained with K2HPO4 and ATP at an IP/OP proportion of 1:3, which was 1.04, 1.09 and 1.30 times higher than K2HPO4 and G6P, Na5P3O10 and ATP, Na5P3O10 and G6P, respectively. The increasing proportion of OP was advantageous for microalgae growth, but disadvantageous for lipid accumulation. Besides, the intra-cellular phosphorus was classified and quantified by 31P NMR spectroscopy to ascertain its metabolism and transformation. Results provided a fresh perspective on the utilization of complex phosphorus sources with microalgae.

The degree of the over-consolidation ratio (OCR) of silty clay affects the soil’s mechanical properties and in situ test results. The present study utilized numerical analysis to investigate the behavior of cone penetration and pore pressure dissipation in typical silty clay soils, while also taking into account the impact of the over-consolidation ratio (OCR). Effective stress finite-element analyses, which accounted for considerable deformation, were carried out at various OCRs. The model assumed the soil as a homogeneous material obeying the modified Cam Clay (MCC) model. The significant advance of this work is the evaluation of the effect of OCR on penetration resistance and pore pressure test data and the calculation formula of OCR and ch in typical silty clay. An inversion method based on the results of piezocone penetration tests was proposed in terms of strength and the over-consolidation ratio of the silty clay, which is of great importance for the inversion of soil parameters in the Yellow River Delta region. This paper presents a consolidation coefficient inversion method of typical normally and over-consolidated silty clays and corrected the disadvantage that traditional conversion methods could not take OCR effects into account.

The thermal conductivity of marine sediments is an important thermophysical parameter in the study of seafloor heat flow and marine engineering construction. Understanding the effect of thermal conductivity of marine sediments in the environment has a major engineering value and theoretical significance. In this work, a modified test method was used to measure the thermal conductivity of silt in the Yellow River Delta under different void ratios, moisture contents, temperatures, and salinities. Results showed that the thermal conductivity of silt in the Yellow River Delta decreased with the increase in the void ratio and increased with the water content. Compared with sand and clay, silt in the Yellow River Delta was the least affected by the void ratio and moisture content. Under low temperatures, the heat transfer of soil was controlled by the average velocity of the phonons; therefore, the thermal conductivity of silt in the Yellow River Estuary increased with temperature. The thermal conductivity of pore water decreased with increasing salinity. Moreover, certain salinity levels resulted in a phenomenon known as the ‘compressing twin electrical layer’, which led to an increase in the contact area between soil particles. With the increase in salinity, the thermal conductivity of silt in the Yellow River Delta experiences an initial decline and a subsequent increase. The proposed thermal conductivity test method is more accurate than the existing technique, and the findings provide a basis for further study on the thermal characteristics of submarine sediments.

The leakage of an enclosure structure will cause abnormal changes in the seepage flow field, which in turn can lead to the deformation of the enclosure structure and affect the surrounding geotechnical body. In this paper, a fiber-optic temperature measurement system is used to detect the location of the seepage points in a station of the Qingdao subway during open pit excavation, and the abnormal variation of the seepage field caused by the seepage points is obtained by numerical calculation and field measurement. Then, numerical simulation is performed to analyze the effects of seepage field anomalies on the deformation of the enclosure structure and surface settlement. It is found that the seepage flow caused by the leakage point has a significant influence on the surface settlement and the deformation of the enclosure structure. With the increase of excavation depth, the deformation of the enclosure structure increases and the maximum deformation position shifts downward. The deformation of the enclosure structure decreases when the leakage point exists. The surface volume also increases gradually with the excavation, and the maximum surface settlement position shifts outward significantly. The settlement range becomes larger when the leakage point exists.

The degree of drainage that occurs during structure-soil interaction is a crucial factor that affects the stress on the structure in the intermediate soil. The consolidation coefficient is the most important index to evaluate partial drainage conditions, but the pore pressure dissipation curve used for consolidation coefficient inversion is also affected by drainage conditions. This paper adopts an effective stress numerical analysis work which combines finite-element penetration analysis and critical-state soil mechanics considering the partial drainage effect through changing the penetration rate. The significant advances of this work are the evaluation of the partial drainage effect on pore pressure test data and the influence mechanism of partial drainage on consolidation coefficient test results of intermediate soil. A modified consolidation coefficient inversion method can describe the pore-pressure response curve for dissipation tests performed in soils where pore pressure has dissipated partially. The modified theoretical relationship of vertical and horizontal consolidation coefficient and the theoretical relationship of ch under partial drainage and undrained condition are given. The consolidation co-efficient inversion method of intermediate soil with high permeability is proposed, and the inversion results are consistent with the actual value.

Soil dilatancy and partial drainage have great influence on the consolidation coefficient assessment of silty soils with clay content of less than 30% in the Yellow River Delta using the CPTu. This paper discussed the effect of soil dilatancy and partial drainage on the pore pressure response and dissipation of piezocone test in shallow silty soil of the Yellow River Delta through variable penetration rate tests in a pressure chamber and a series of supplementary soil element tests. The results show that the pore pressure dissipation curve is affected by soil type and degree of consolidation. The soil dilatancy is the key factor affecting consolidation coefficient inversion of shallow silt and silty clays. The initial pore pressure is negative and the pore pressure increases to umax first, but the umax value is very small in the Yellow River Delta silt. The inversion method used for shear contractile soil cannot be used to invert the mechanical properties of shallow silty soil directly, and a new consolidation curve normalization method is proposed. This paper provides a reference for the consolidation coefficient inversion of CPTu data in the Yellow River Delta area.

The vibration produced by blasting excavation in urban underground engineering has a significant influence on the surrounding environment, and the strength of vibration intensity involves many influencing factors. In order to predict the space-time effects of blasting vibration more accurately, an automatic intelligent monitoring system is constructed based on the rough set fuzzy neural network blasting vibration characteristic parameter prediction model and the network blasting vibrator (TC-6850). By setting up the regional monitoring network of monitoring points, the obtained monitoring data are analyzed. An artificial intelligence model is used to predict the influence of stratum condition, excavation hole, and high-rise building on blasting vibration velocity and frequency propagation. The results show that the artificial intelligence prediction model based on a rough set fuzzy neural network can accurately reflect the formation attenuation effect, hollow effect, and building amplification effect of blasting vibration by effectively fuzzing and standardizing the influencing factors. The propagation of blasting vibration in a soil–rock composite stratum is closely related to the surrounding rock conditions with a noticeable elastic modulus effect. The hollow effect is regional, which has a significant influence on the surrounding ground and buildings. Besides, the blasting vibration of the excavated area is stronger than that of the unexcavated area. The propagation of blasting vibration on high-rise buildings was complicated, of which the peak vibration velocity is maximum at the lower level of the building and decreased with the rise of the floor gradually. The whip sheath effect appears at the top floor, which is related to the blasting vibration frequency and the building’s natural vibration frequency.

In engineering blasting, the slope surfaces in the blasting area exert various effects on the blast vibration velocity. For example, the slope effect and the whipping effect are generated in the slope area, which will influence the blast vibration velocity. The slope area is the key protection area for many projects; therefore, it is of practical value to explore the influence of slope surface on blast vibration speed for the prediction of blast vibration and protection against it. The influence of slope effect and whipping effect on blast vibration velocity in the slope area was analyzed by numerical simulation and fitting. The field monitoring data were fitted to the blast vibration velocity prediction formula. According to the obtained fitting formula, we inferred that vibration speed amplification occurred in the slope area. Numerical simulation was carried out using the ANSYS/LS-DYNA program. Using the above two methods, whether the slope effect and whip tip effect occurred in the study area was verified. By numerical simulation, we established three-dimensional (3D) slope models for four different working conditions. We simulated the complete blasting process and the consistency between the simulation results, and the field data proved the reliability of the numerical simulation. Based on the results of the numerical simulation, we explored the variation of blasting vibration velocity under different height difference conditions. Finally, we explored the distribution law of blasting vibration at the slope surface and inside the slope.

According to the variation pattern of the solar magnetic field polarity and its relation to the relative sunspot number, we established the time series of the sunspot magnetic field polarity index and analyzed the strength and polarity cycle characteristics of the solar magnetic field. The analysis showed the existence of a cycle with about a 22-year periodicity in the strength and polarity of the solar magnetic field, which proved the Hale proposition that the 11-year sunspot cycle is one-half of the 22-year solar magnetic cycle. By analyzing the atmospheric temperature field, we found that the troposphere and the stratosphere in the middle latitude of both the northern and southern hemispheres exhibited a common 22-year quasicycle in the atmospheric temperature, which is believed to be attributable to the 22-year solar magnetic cycle.

The distributions and environmental quality assessments of heavy metals Cu,Pb,Zn,Cr,V,Ni in the surface sediments in the central region of the Bohai Sea were performed.The contents of heavy metals Cu,Pb,Zn,Cr,V,Ni were 22.50,24.26,64.27,59.66,67.91 and 30.57?g/g,respectively.The contents were high in the Haihe River mouth and central region of the Bohai Bay,the mud area in the central study region and the coastal area of south Liaodong Peninsula;while that were low in the east of study area and the northern Bohai Bay.They were in middle level compared with that in other domestic and foreign regions.The heavy metals mainly came from natural sources,but were affected significantly by human activities.The environment quality evaluation of the sediment was carried out by the methods of geological cumulative index and ecological risk assessment.There were light polluted or non-pollution in the north Bohai Bay and the shallow of the central Bohai Sea at the east of study area;and light polluted along the coast of the south Liaodong Peninsula;while the western and southern areas of Bohai Bay,the central mud area of the Bohai Sea were medium polluted.The primary pollution element is Pb,which followed by Cr,Zn,V.The pollution of Cu and Ni were less.

Qixia Yashan area is located at the east of the North China platform.The geochemical studies about the porphyritic granodiorites in this area shows that the rocks belong to calc-akaline and metalumious series.The MORB-normalized spider diagram of trace elements reveals enriching LILE of Ba and Sr,and lacking of HFSE of Nb,Ta,Hf and Y.The ratio of K/Rb is 295.34~388.88 and Rb/Sr is 0.21~0.29.The spider diagram of rare earth element,show relative smooth,weak negative abnormal of Eu and right steep patterns.∑ LREE/∑ HREE is 9.14~12.22.They all indical well differentiation between LREE and HREE.Through the analysis of strural factors the genesis of Yashan granodiorite is that sabduction of Pacific plate to Eurasian plate causes mantle plume activlty,which produces mantdiapir and crust partial melting,then form crust-mantle magma,and the furture invasion form the granodiorite.

Organic carbon and total nitrogen were analyzed for the 163 surface sediment samples collected from the Bohai Bay during the summer of 2006.In this paper,we mainly discuss the distribution of total organic carbon(TOC) and its contributors.Results show that the concentrations of TOC are high in the southern and low in the northern part of the study area.There is a positive correlation between TOC and median diameter of grain sizes of sediments,indicating that the distribution of TOC is controlled by depositional environment to some degree.A good correlation exists between TOC and TN in surface sediments.There is small amount of inorganic nitrogen in surface sediments,which may influence the application of TOC/TN ratios to identify the source of organic matter.Therefore,we removed the influence of inorganic nitrogen to the calculation.C/N ratios of samples in study area vary from 4 to 17 with an average at 9,suggesting the mixed origin of TOC from both marine and terrestrial sources.The contributions of terrestrial and marine sources to TOC were estimated,and the results indicate that the input of terrigenous organic carbon is the dominant contributor to the TOC in the study area,especially in the nearshore and estuarine areas.

Successive filtration and comparison show that the stratosphere air temperature in 10 hPa-layer of the Northern Hemisphere (NH) in July continuously increases, which is associated to the increases in greenhouse gases mostly CO 2 , volcanic activities, and solar activity, demonstrating the follows. (a) The increase in CO 2 concentration is largely consistent with that of the stratosphere air temperature in 10 hPa-layer of the NH in July. However, the increase in the air temperature is not in a linear pattern, during which several cooling events interrupt. The cooling events between late 1960s and late 1970s are remarkable ones and so is the one before mid 1990s. Analysis shows that these events are induced by volcanic activities and solar activity. (b) The CO 2 -free variation in the stratosphere air temperature in 10 hPa-layer of the NH is consistent with that of the solar magnetic index. The wave crests and wave troughs of the two curves are consistent in phase, and the curve of solar magnetic index leads the other slightly. In other words, when the solar magnetic pole is southward, a warming in the NH stratosphere corresponds; and on the contrary, the northward solar magnetic pole corresponds to a cooling event. The variation in solar magnetic polarity strongly impacts the variation in the stratosphere temperature.

Field observations of suspended particulate matter (SPM) in the Bohai Bay, China have not been widely reported. The aim of this paper is to describe the horizontal and vertical distribution of mass and volume concentrations of SPM, respectively, based on observed data at 312 stations in the northern Bohai Bay during summer of 2006. A numerical model ECOMSED coupled with a sediment transport module was also established to further discuss the mechanism of the thermocline effect on the vertical distribution of SPM. The mass concentrations of SPM exhibited high inshore values and low offshore values in the horizontal distribution; while in the vertical direction, characteristics of the volume concentration of SPM can be divided into two types: one with a sharp peak at depth of 10-15 m and another without. The peak value at the depth of the thermocline was resulted from concentrated phytoplankton. A numerical experiment further displayed that the thermocline can also prevent particles from being resuspended upward. (C) 2010 Elsevier Ltd. All rights reserved.

为了探索北大西洋涛动形成的大尺度大气物理场背景条件和外部强迫因子,通过对比分析、相关分析和环流系统温压场垂直结构分析得到:（1）强火山活动指数距平与冰岛低压和亚速尔高压海平面气压场（SLP）距平总体相关函数符号相反,强火山活动指数与冰岛低压SLP为反相关,与亚速尔高压SLP为正相关,就是说火山活动指数异常引起了高纬度冰岛低压和中低纬度亚速尔高压海平面气压场相反的变化趋势,形成高低纬之间海平面气压场反相振荡;（2）夏季7月亚速尔高压对流层中下层至海平面,温度距平中心和位势高度距平中心距平符号大致正正相对负负相对,说明夏季亚速尔高压为深厚暖性系统,低层温度升高亚速尔高压加强,低层温度降低亚速尔高压减弱,所以火山活动指数与亚速尔高压SLP均呈反相关关系;冬季1月对流层中下层至海平面,温度距平和位势高度距平符号大致正负相对,说明冬季亚速尔高压为浅薄系统,低层温度升高亚速尔高压减弱,低层温度降低亚速尔高压加强,所以火山活动指数与亚速尔高压SLP均呈正相关关系;（3）冬季1月冰岛低压对流层中下层至海平面,温度距平中心和位势高度距平中心距平符号大致正正相对负负相对,说明冬季冰岛低压为深厚冷性系统,低层温度升高冰岛低压减弱,低层温度降低冰岛低压加深,所以火山活动指数与冰岛低压SLP均呈反相关关系;夏季7月对流层中下层至海平面,温度距平和位势高度距平符号大致正负相对,说明夏季冰岛低压为浅薄系统,低层温度升高冰岛低压减弱,低层温度降低冰岛低压加深,所以火山活动指数与冰岛低压SLP均呈正相关关系;（4）.由于对流层中下层至海平面冰岛低压和亚速尔高压冬、夏季温压场结构特点基本相反,火山活动指数异常在两个环流系统中引起了相反响应,导致高低纬之间海平面气压场反相振荡,形成了影响广泛的著名的北大西洋涛动现象。

The M(s)7.4 earthquake occurred on 18 July 1969 was the only strong earthquake that has been recorded by seismometers in Bohai Sea. Now arguments about this large earthquake are focused on its causative fault. In 2005 similar to 2008, we finished three cruises in the epicenter region and collected several hundreds high-resolution acoustic surveying data, including shallow penetrated single channel data, sidescan sonar data and CHIRP data. This paper reports study results of these new acoustic data. A micro depression belt is newly found in Holocene sediments 2 similar to 3 m beneath seabed in the epicenter region and it strikes NE30 degrees, is 20 km long and 3 km wide. CHIRP data reveal that depositional interface formed at 5000 a B. P. has a 1.5 m vertical offset in the belt. The depression belt, BZ28 fault and aftershocks distribution of 1969 earthquake coincide in position, so it can be assumed that the depression belt is formed by BZ28 fault and the deformation of the bottom of seismic sequence A is caused by 1969 earthquake. BZ28 fault is the causative fault of this large earthquake and it is a sub-fault in the Tan-Lu Fault Zone and strikes NE30 degrees. Shallow penetrated single channel seismic data show that it is active during the late Holocene. According to sediments age and vertical offset, we calculate the vertical slip rate of BZ28 fault since late Pleistocene. The result shows that activity intensity of BZ28 fault has the trend of increasing from 0.05 mm/a since the late Pleistocene to 0.3 mm/a during the Holocene.

Based on the analysis of particulate organic carbon (POC) and particulate nitrogen (PN) of the 155 samples collected from the 41 stations in the Bohai Bay and its adjacent sea, during the summer period in 2006, combining with the data of environmental hydrology, the spatial distributions, influential factors and source of POC and PN were discussed. The results show that the concentrations of POC and PN range from 155.9 microg/L to 1363.1 microg/L, 26.2 microg/L to 225.5 microg/L, with average values of 429.5 microg/L and 111.5 microg/L, respectively. The spatial distribution patterns of POC and PN are similar in the study area. The concentrations of POC and PN in the coastal areas are higher than those in the outer shelf, and the concentrations of POC and PN are higher at the bottom water layers than those at the surface water layers. Biological effect, thermocline and concentration of TSM are the main factors affecting the spatial distribution of POC. There exists a positive correlation between POC and TSM, indicating that the source of TSM is an important factor for the POC. The POC/PN ratio varies from 3.4 to 7.0, but this result is influenced by the presence of particulate inorganic nitrogen (PIN). According to the univariate linear regression model between POC and PN, the concentrations of PIN in the samples were evaluated. Removing the content of PIN in the samples, the POC/PON ratio ranges from 5.5 to 19.8 (PON= PN - PIN), suggesting that the terrestrial input originating from the nearby rivers is also an important source of POC, in addition to the major contribution from the marine primary production. This method could be applied to identify the source of POC in other coastal areas of China.