语言及族裔的对立与杂糅——论安扎杜尔“边土”书写中的语言跨界现象与族裔身份定位

墨西哥裔美国女作家安扎杜尔的《边土》是当代跨越边界和学科的奇卡纳文学代表性作品。这部作品的典型特征是语言的"混血"与杂糅的现象。安扎杜尔认为语言是身份认同的主要依据之一,因而她在创作中通过语言杂糅的表现手法表达了她对美国"主流文化观"传统观念的否定及颠覆,并通过文学创作中的新语言体系来确立美国少数族裔与白人群体之间的"混血"关系,在消解少数族裔与白人之间以及族裔内部性别之间"非此即彼"二元论对立关系的同时,构建起"尼潘特拉"中间状态的身份认同体系,为美国当代族裔文学研究提供了可供借鉴的崭新视角。

种族、性别和后现代主义——评美国墨西哥裔女作家格洛丽亚·安扎杜尔和她的《边土:新梅斯蒂扎》

拉美裔文化在美国引起越来越多的关注 ,奇卡纳女性主义批评的创始人格洛丽亚·安扎杜尔凭借独特的视角 ,执拗地挖掘美国墨西哥裔问题及其文化历史根源。她的代表作《边土 :新梅斯蒂扎》采用后现代主义书写策略 ,从文化、种族、阶级和性别等方面探讨美国墨西哥裔问题 ,引发了褒贬不一的广泛争议。

《边土》对墨西哥传统文化中母性原型的重构

美国著名奇卡纳作家安扎杜尔的代表作《边土》以其独特的写作技巧与杂糅的语言讲述墨裔美国人的族裔身份定位问题,成为20世纪关于文化与身份建构的宣言。墨西哥文化是奇卡纳文学的肥沃土壤,而神话是民族文化的源头,安扎杜尔采用全新的女性主义视角重新诠释墨西哥神话传说中的母性原型,以此来对抗"主流"社会的男权文化和种族歧视,彰显奇卡纳文学鲜明的政治立场与文化特色。

Influence of the boundary effect on the mechanical response test of pavement cushion under the wetting effect of silt

Through a self-developed model test system,the mechanical properties of silt and the deformation characteristics of airport runways were investigated during the period of subgrade wetting.Based on the test results,the reliability of the numerical simulation results was verified.Numerical models with different sizes were established.Under the same cushion parameter and loading width ranges,the effects of the cushion parameters and loading conditions on the mechanical responses of the cushion before and after subgrade wetting were analyzed.The results show that the internal friction angles of silt with different wetting degrees are approximately 34°.The cohesion is from 8 to 44 kPa,and the elastic modulus is from 15 to 34 MPa.Before and after subgrade wetting,the variation rates of the cushion horizontal tensile stresses with the same cushion parameters and loading width ranges are different under the influence of boundary effects.After subgrade wetting,the difference in the variation rates of the cushion horizontal tensile stresses under the same cushion parameter range decreases compared with that before subgrade wetting;however,this difference increases under the same loading width range.Before and after subgrade wetting,the influence of the boundary effect on the mechanical response evaluation of the cushion is not beneficial for optimizing the pavement design parameters.When the cushion thickness is more than 0.25 m,the influence of the boundary effect can be disregarded.

逆作法及其在深基坑中的应用

文章对逆作法施工过程中的差异沉降、桩承载力、“盆”边土宽度问题、逆作法施工的特点等进行了探讨,并提出解决方案。

Influence of Gradient on Stability of Soil Slope Containing Roots

Abundant herbaceous and shrub roots play an important role in preventing water and soil erosion and increasing shallow slope stability. In order to make a quantitative analysis on the contribution of root system to slope stability under dif- ferent slope gradient, an unconsolidated and undrained triaxial compression test was conducted to measure the shear strengths of soil and root-soil composite in the two slopes in eastern Qinghai Province. In addition, under the protection of plant roots, the effect of gradient on stability of soil slope was investigated by limit equilibrium method. The results showed that the stability coefficient of soil slope planted with two kinds of brush was decreased with the increase in slope gradient, and the sta- bility coefficient increment of soil slope containing Atriplex canescens roots was higher than that containing Caragana korshinskii roots. When the slope gradient ranged from 25° to 50°, the stability coefficient of soil slope planted with Atriplex canescens or Caragana korshinskii ranged from 0.80 to 1.38. However, when the slope gradient exceeded 55°, the increment of stability coefficient of soil slope became small.

Study on the Spatial Pattern Changes of Land Use Based on Fractal Dimensions in Tianjin New Coastal Area

[Objective] The aim was to discuss the spatial pattern changes of land use in Tianjin new coastal area based on fractal dimensions.[Method] By dint of remote and geographic information system technology to obtain the data of urban land use in new coastal area from 1993 to 2008,the boundary dimension,radius dimension and information dimension of each land use type were calculated based on fractal dimension.In addition,the revealed land use spatial dimension changes characteristics were analyzed.[Result] The spatial distribution of each land use type in new costal area had distinct fractal characteristics.And,the amount and changes of three types of dimension values effectively revealed the changes of complicatedness,centeredness and evenness of spatial pattern of land use in the study area.The boundary dimension of unused land and salty earth increased incessantly,which suggested its increasing complicatedness.The boundary of the port and wharf and shoal land was getting simpler.The radius dimension of the cultivated land was larger than 2,which suggested that its area spread from center to the surroundings;the one in salty land and waters distributed evenly within different radius space to the center of the city;the one in other land use types reduced gradually from center to the surroundings.The information dimension value in the woodland and orchard land,unused land and shoal land was small,and was in obvious concentrated distribution;the spatial distribution of cultivated and salty land concentrated in the outside area;the construction area in the port and wharf spread gradually on the basis of original state;the spatial distribution of waters and residents and mines were even.[Conclusion] Applying fractal dimensions to the study of spatial pattern changes of urban land use can make up for some disadvantages in classical urban spatial pattern quantitative research,which has favorable practical value.

Ecological suitability evaluation for urban growth boundary in red soil hilly areas based on fuzzy theory

The fuzziness exists in spatial distribution of geographic data of land suitability evaluation processes,which makes it difficult to quantify land boundaries by using traditional binary logic-based overlay model.Aiming at this limitation,an ecological suitability evaluation analysis model was presented based on fuzzy theory and a research on urban growth boundary(UGB) of the Great-Hexi Leading District(GHLD) of Changsha was conducted.With the support of GIS,RS and MATLAB,slope,elevation,vegetation,soil productivity,soil permeability,water body and land use are selected as the input of model according to the characteristic properties of soil and terrain in red soil hilly areas.The running result of this model indicates that the ratios of highly suitable land,suitable land,moderately suitable land and unsuitable land in GHLD are 18.75%,10.31%,64.16%,6.78%,respectively.This result accords with spatial structure worked out by Space Development Strategy Planning of GHLD,Based on this result,several suggestions are made to guide UGB developments in future.

Energy analysis of geosynthetic-reinforced slope in unsaturated soils subjected to steady flow

Soils are actually unsaturated in nature. In the present study, a stability analysis of a geosynthetic-reinforced slope in unsaturated soils subjected to various steady flow conditions is conducted based on limit analysis. Work rate by apparent cohesion due to matric suction is calculated based on the effective stress-based equation. Analytical expression of the required cohesion/stability number of slope is derived from the energy balance equation. An optimization code is programmed to capture the optimized solution of the stability number. Comparison is made to verify the present work and a parametric analysis is conducted to investigate the effects of soil type, infilitration rate, reinforcement strength and soil suction on slope stability afterwards. A set of numerical solutions is presented at the end of the paper for preliminary design purposes.

Infiltration regulation and stability analysis of soil slope under sustained and small intensity rainfall

Rainfall infiltration depth and mode can severely influence slope stability.With the sustained rainfall,the influenced region of slope gradually expands.By using the Green-Ampt model to the soil slope,infiltration regulation was discussed under sustained and small intensity rainfall.And the infiltration rate of unsaturated soil was proposed according to the saturated infiltration theory.Because of the changing of initial moisture content in depth of slope,the saturated or unsaturated infiltration rate and depth could also be changeable with the sustained rainfall infiltration.Based on the principle of strength reduction,the calculation model of slope safety factor was established under different initial moisture contents and infiltration modes.Then,the slope stability was quantitatively analyzed through software FLAC3D.The calculation results of soil slope engineering show that there is a shorter period for slope stability under different initial moisture contents and unsaturated infiltration ways at the slope wetting front.The stability period of slope is 33.3%according to different initial moisture contents of wetting front less than that of the same initial moisture content of wetting front.And the slope is easier to fail under the unsaturated infiltration.The results agree well with the actual situation under sustained and small intensity rainfall.

Numerical experimental study on optimum design of anchorage system for Xiashu loess slope

In FLAC ^(3D),cable element or modified pile element can be used to build slope anchoring model.However,the difference between the two structural elements and their influence on the calculation results have not been studied in depth.In order to solve this problem,the Xiashu loess slope anchoring models based on cable element and modified pile element were constructed respectively.A variety of anchoring schemes were designed by orthogonal experiment method,and then they were brought into the model for calculation and the calculation results were analyzed by range analysis and variance analysis.The results show that the modified pile element can bear the bending moment and reflect the strain softening property of the grout.From the perspective of slope safety factor,the anchorage length and anchor bolt spacing are the main factors affecting the stability of the slope,and the anchorage angle is the secondary factor.The grout in cable element is assumed to be an elastic-perfectly plastic material,so the safety factor of the slope can be significantly increased by increasing the length of the anchor bolts.This will bring potential risks to the slope treatment project.Therefore,in the calculation of the slope anchoring model,the modified pile element is more suitable for simulating the anchor bolt.

Back analysis for soil slope based on measuring inclination data

Based on the analysis of several objective functions,a new method was proposed.Firstly,the feature of the inclination curve was analyzed.On this basis,the soil could be divided into several blocks with different displacements and deformations.Then,the method of the soil division was presented,and the characteristic of single soil block was studied.The displacement of the block had two components:sliding and deformation.Moreover,a new objective function was constructed according to the deformation of the soil block.Finally,the sensitivities of the objective functions by traditional method and the new method were calculated,respectively.The result shows that the new objective function is more sensitive to mechanical parameters and the inversion result is close to that obtained by the large direct shear apparatus.So,this method can be used in slope back analysis and its effectiveness is proved.

Force analysis of pile foundation in rock slope based on upper-bound theorem of limit

Based on the characteristic that the potential sliding surfaces of rock slope are commonly in the shape of either line or fold line,analysis thought of conventional pile foundation in the flat ground under complex load condition was applied and the upper-bound theorem of limit analysis was used to compute thrust of rock layers with all possible distribution shapes. The interaction of slope and pile was considered design load in terms of slope thrust,and the finite difference method was derived to calculate inner-force and displacement of bridge pile foundation in rock slope under complex load condition. The result of example shows that the distribution model of slope thrust has certain impact on displacement and inner-force of bridge pile foundation. The maximum displacement growth rate reaches 54% and the maximum moment and shear growth rates reach only 15% and 20%,respectively,but the trends of inner-force and displacement of bridge pile foundation are basically the same as those of the conventional pile foundation in the flat ground. When the piles bear the same level lateral thrust,the distribution shapes of slope thrust have different influence on inner-force of pile foundation,especially the rectangle distribution,and the triangle thrust has the smallest displacement and inner-force of pile foundation.

Stability analysis of cohesive soil embankment slope based on discrete element method

In order to study the safety factor and instability process of cohesive soil slope, the discrete element method(DEM) was applied. DEM software PFC2 D was used to simulate the triaxial test to study the influence of the particle micro parameters on the macroscopic characteristics of cohesive soil and calibrate the micro parameters of DEM model on this basis. Embankment slope stability analysis was carried out by strength reduction and gravity increase method, it is shown that the safety factor obtained by strength reduction method is more conservative, and the arc-shaped feature of the sliding surface under the gravity increase method is more obvious. Throughout the progressive failure process, the failure trends, maximum displacements, and velocity changes obtained by the two methods were consistent. When slope was destroyed, the upper part was cracked, the middle part was sheared, and the lower part was destroyed by extrusion. The conclusions of this paper can be applied to the safety factor calculation of cohesive soil slopes and the analysis of the instability process.

Vane Shear Strength Based Stability Analysis of Slopes in Unconsolidated Soft Clay

In-situ vane shear test is frequently performed to determine shear strength for slope stability analysis in Tianjin New Harbor.However,the soil shear strength varies with the shear plane orientation.A possible means to reduce the effect of directional dependency of shear strength is to convert the in-situ vane shear strength into undrained shear strength parameters.A method of converting in-situ vane shear strength into undrained shear strength parameters is presented.The shear strength parameters determined for all of the in-situ vane shear strengths are subjected to statistical regression analysis to take into consideration the possible effect of non-homogeneity in the soft clay deposit.Using the regressed shear strength parameters,slope stability analyses are performed for five existing soil slopes.The results of stability analyses indicate that the safety factors obtained from the converted parameters reflect the state of the slopes analyzed much better than those obtained from in-situ vane shear strength and laboratory consolidated-undrained and unconsolidated-undrained strength parameters.It is concluded that the presented methsod of determining undrained shear strength parameters for in-situ vane shear strength is effective.

The stability analysis of expansive slope in Jing-Yi Expressway

This paper firstly introduces the distribution of weathered layers, and then presents the relationship between watercontent and expansive force and the working model of expansive forces in expansive soil slopes. Taking the expansive soil slope ofJing-Yi Expressway as example and applying the Slices Method, this paper puts forward the stability calculation method con-sidering the effect of expansive forces, and also proposes the treatments.

3D stability assessment of stepped slopes in inhomogeneous soils

Stability assessment of slopes has historically been performed assuming soils to be homogeneous in two-dimensional(2D) cases. In real cases, soils are usually inhomogeneous, and each slope collapse indicates a three-dimensional(3D) nature. Based on a 3D rotational failure mechanism, this work develops an approach to account for the impact of the vertical strength inhomogeneity on the 3D stability of stepped slopes. Seismic actions are taken into account by introducing the concept of a horizontal seismic coefficient. An upper-bound expression for stability factors is derived in the light of the kinematic approach, and the most critical solution is obtained from an optimization programming. In comparison with the previously published solutions, the validity of the proposed method is shown. A sensitivity analysis is carried out to discuss parametric effects on the stability of 3D stepped inhomogeneous slopes.

A new method for the stability analysis of geosynthetic-reinforced slopes

This paper is concerned with the stability analysis of reinforced slopes.A new approach based on the limit equilibrium principle is proposed to evaluate the stability of the reinforced slopes.The effect of reinforcement is modeled as an equivalent restoring force acting the bottom of the slice and added into the general limit equilibrium(GLE) method.The equations of force and moment equilibrium of the slice are derived and corresponding iterative solution methods are provided.The new method can satisfy both the force and the moment equilibrium and be applicable to the critical failure surface of arbitrary form.Furthermore,the results predicted by the proposed method are compared with the calculation examples of other researchers and the centrifuge model test results to validate its correctness and effectiveness.

Performance of Slope Behavior Indicators in Unsaturated Pyroclastic Soils

Landslide risk is increasing in many parts of the world due to growth of population and infrastructures. Therefore, an effort has to be made in developing new and cheap sensors for areas susceptible of landslides to continuously control the slope behaviour, until approaching failure conditions. The paper reported experimental data from smallscale physical models about the performance of Time Domain Reflectometry(TDR) and optical fibres, which act as the indicators of the incoming failure of slopes covered by unsaturated granular soils. Obtained results appear encouraging, since both sensors provide continuous information about the state of the slope, in terms of water content profiles and ongoing deformations, induced by rainwater infiltration, even immediately before the triggering of a fast landslide.

Effect of Land Use Conversion from Rice Paddies to Vegetable Fields on Soil Phosphorus Fractions

Excess phosphorus （P） from agricultural soils contributes to eutrophication in water bodies. Samples （n = 60） were taken from sites where rice paddies have been converted to vegetable fields for 0, 〈 10, 10-20, and 〉 20 years and analyzed for five inorganic P （Pi） fractions, three organic P （Po） fractions, and several soil parameters to investigate how land use conversion affects Pi and Po fractions in a peri-urban area of China with soils characteristic of many agricultural areas of Asia. Significant increases of 33, 281, 293, and 438 mg kg-i were found for soluble and loosely bound Pi （SL-Pi）, aluminum-bound Pi （Al-Pi）, calcium-bound Pi （Ca-Pi）, and iron-bound Pi （Fe-Pi）, respectively, after conversion from rice paddies to vegetable fields. Most of the increase in Pi was in the form of Fe-Pi, which increased from 8% of total P （TP） on paddy soil to 31% on the soil with 〉 20-year vegetable cultivation, followed by Al-Pi, which increased from 2% to 19% of TP. For Po fractions, there was no significant change in P concentrations. The conversion of land use from paddy fields to high intensity vegetable fields was causing significant changes in soil P fractious. Management practices were causing a buildup of soil P, primarily in the Fe-Pi fraction, followed by Ca-Pi and Al-Pi fractions. If current trends continue, a 30%-70% increase in TP could be expected in the next 20 years. Farmers in the area should reduce P application and use to maximize P uptake.