学术会议英语报告——黄龙阳_学术会议常用英语

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学术会议英语 期末论文

学号: 2015000360 姓名：黄龙阳

学院：土木工程与建筑学院

专业：土木工程 班级：

A（6）

2016年5月

地基处理效果检测方法研究

黄龙阳

摘要：随着我国各种建设项目的实施，由于各种场地的地质条件特性，往往需要对其进行地基加固处理，而目前的加固处理方法种类繁多，效果差别很大。因此寻找有效的地基处理效果检测方法就显得尤为重要。本文就目前工程中应用较多的地基处理检测技术进行探讨和归纳。

关键词：地基处理；效果；检测方法 前言

随着我国经济技术的迅速发展，各种建设项目开始实施，但通常由于场地地质条件的特殊性，需要对建设场地进行地基加固处理。目前在实际工程建设过程中应用的地基处理方法很多，堆载预压、强夯法、加筋法、换填法、振冲桩、旋喷桩、地基土改良等，但往往由于地基处理方法本身的局限性和施工过程中的人为因素，造成地基处理效果参差不齐。而一个合格的工程场地地基，是建设工程质量安全的重要保障，因此，检测地基加固处理效果的检测技术发挥着越来越重要的作用。目前工程中应用于地基处理效果检测的方法主要有荷载试验、动力触探试验、静力触探试验、十字板剪切试验、波速试验、取芯试验等，但各种试验方法本身适用条件有限，试验精度相差很大。本文结合一些工程实例，对这些检测方法的应用和效果进行探讨。地基处理效果检测试验研究

目前很多学者对地基加固处理效果检测做了各种各样的研究，并对各种方法的优缺点进行了探讨，本文以下仅将工程中应用比较多的进行阐述和归纳。2.1 地基静载荷试验

基静载荷试验是一种精度较高，分析结果与实际吻合度较好的试验方法，用其进行地基承载力测定和地基沉降计算相对准确，但其成本较高，技术要求严格，且试验周期相对较长，一般大型项目的场地勘察均要求进行此项试验。2.1.1 静载荷试验简述 静载荷试验模拟建筑物地基土的受荷条件，在刚性承压板上加荷，荷载通过承压板均匀传递给地基，以测定天然埋藏条件下地基土的变形特性，从而评定地基土的承载力，计算地基土的变形模量和估计基础的沉降量，可以比较直观的反映地基土的变形特性。地基承载力确定方法是：最后当压力－沉降曲线上有比例界限时，取该比例界限所对应的荷载值；当极限荷载小于对应比例界限的荷载值的2倍时，取极限荷载值的一半；当不能按上述两款要求确定时，可取 s/b=0.01所对应的荷载，但其值不应大于最大加载量的一半[1]。2.1.2 静载荷试验评价实例总结

王文奎[2]等采用工字钢和堆料组成压重平台反力系统，用压重平台反力法对长江沿岸某码头后方陆域地基处理工程进行质量检测。预压地基荷载板为边长1m的方形板，由于该工程场地地基处理设计承载力特征值为120kpa，故该次试验最大加载为设计值的2倍，为240kpa，按24kpa每级分级加载，并在加载过程中进行沉降观测，地基承载力特征值的确定。该次试验共计检测20处，p-s曲线上可以看出，当最大加载至240kpa时，所有测点均未达到极限状态，最大沉降量为8.400mm，最小沉降量为6.200mm，根据承载力特征值的取值原则，取最大加载量的一半，即240kpa/2=120kpa为该点处理后地基的承载力特征值，所有测点的承载力均满足设计要求。该工程采用静载荷试验对地基处理进行了评价，说明了该场地经过地基处理，达到了该场地设计的地基承载力120kpa。2.2 十字板剪切试验

十字板剪切试验由于其自身的适用条件限制，一般在沿海地区的软土场地应用较为普遍，而在一些碎石土场地则无法用其进行场地地基处理效果的评判。2.2.1 十字板剪切试验简述

试验时，逆时针方向摇动扭力箱装置小摇手，以每10s转动1°的速度匀速转动，当试验达到峰值或者稳定值后，再测试1min，如试验数据正常，记录峰值数据，根据该数值计算原状土抗剪强度；完成抗剪强度测定后，顺扭转方向连续转动探杆6圈，按照以上步骤进行操作，测定重塑土的不排水抗剪强度。2.2.2 十字板剪切试验评价实例总结

王文奎[2]等采用十字板剪切试验对长江沿岸某码头后方陆域地基处理工程进行质量检测。该次试验共8孔，每孔18个测点，对各孔的检测数据进行统计，通过与原地质勘察资料相比较可知，地基土的抗剪强度有了大幅度提高，地基处理达到了预期效果。2.3 轻型触探试验

轻型触探指N10轻型动力触探仪，其质量较轻，设备简单，应用广泛，操作简便，成本较低，在一些软土地区应用十分广泛。2.3.1 轻型触探试验简述

其利用一定的锤击能量，将带有探头的探杆打入土中，按贯入的难易程度来评价土的性质，主要用于素填土及碎石土地层，并可连续贯入，能在其试验深度范围内不断测得土层的力学特性及变化规律[1]。2.3.2 轻型触探试验评价实例总结

王文奎[2]等采用轻型动力触探试验对长江沿岸某码头后方陆域地基处理工程进行质量检测。现场对56根水泥搅拌桩桩顶下2m范围内的桩头进行了检测，试验结果表明桩顶下2m范围内每30cm锤击数为64-78击，设计值：N10>35击/30cm，检测范围内桩身水泥土均匀，质量满足设计要求。2.4 取芯试验

取芯试验即钻取地基处理后的地基土，然后进行室内试验，用以评价其地基处理后的效果，在一些大型工程中应用也较为普遍。2.4.1 取芯试验简述

对采用旋喷桩、振冲桩、搅拌桩进行地基土处理的场地，在对地基桩取芯试验中，其目的主要是检测桩身混凝土质量情况，检查桩身混凝土胶结状况、有无气孔、松散或断桩等；检查桩底持力层的岩土性状和厚度是否符合设计或规范要求，并核对施工记录桩长是否真实[3]。2.4.2 取芯试验评价实例总结

王文奎等采用取芯试验对长江沿岸某码头后方陆域地基处理工程进行质量检测，共完成16根水泥搅拌桩的检测工作，取芯试验无侧限抗压强度48组，桩身芯样成型长度平均8.5m，成型段芯样成短-中柱状，断口吻合较好，桩身8.30m以下部分桩芯样不成型，未形成强度。芯样强度：共完成强度试验48组，无侧限抗压强度平均值为3.1mpa。

钱归[3]对广明高速公路广州段软基处理后的路基进行取芯检测，其结果岩芯[2]采取率均接近100%，采取率65.4%-74.4%。芯样连续、完整、胶结好、呈长柱状，混凝土桩抗压强度代表值为22.1Mpa，说明该软土地基进行处理后达到了地基处理设计要求。2.5 波速试验

波速试验也是地基处理效果检测的常用手段之一，其设备简单，操作简便，价格相对较低，适用范围较广。2.5.1 取芯试验简述

在地面上进行竖向激震时，均会在其表面附近层状连续介质中产生瑞雷波，它的特点是能量大，传播速度低，频率低，随时间衰减慢，易于识别。在层状介质中，瑞雷波法具有频散特性，在同一地段求出一系列频率的瑞雷波速，就可得到一条瑞雷波频散曲线，不同波长的瑞雷波的传播特性反映了不同深度岩土介质的运动学特性，由频散曲线可以反演地下速度界面的分层厚度和速度结构，以确定每层岩土体的速度和深度参数。2.5.2 取芯试验评价实例总结

史慧杰[4]对青岛北海西湾造修船基地填海造陆区地基处理后采用了瑞雷波测试，其测试曲线反映了表层填石密实度不均匀，变化较大，6.2m以下波速逐渐增大，到11.2m波速变化减小，说明了随着深度增大，填石的密实度也增大，但到11.2m以下，波速突然变小，反映了1.2m进入了混合层；12m-12.9m曲线呈直线状态，波速不变，反映了12m-12.9m进入了淤泥层；12.9m以下波速急剧增大到452.5m/s，说明12.9m以后进入强风化基岩。钻探结果和面波试验结果基本一致。存在的问题

由于场地条件本身是复杂多变的，地基处理过程中由于方法的选择不同和施工过程的人为因素影响，将造成其结果有很大的差异，因此对地基处理效果进行检测就尤为重要。但是在实际操作过程中，由于各种方法的局限性和地下情况的复杂性，所以往往需要多中方法综合使用，达到相互验证的目的。同时，也要求我们不断探索，对已有方法进行完善并寻找新的更为有效的技术手段

参考文献

[1] 汤定一.强夯技术加固机理与质量检测研究.湖南大学硕士学位论文，2002.[2] 王文奎.软土地基处理效果检测技术探讨.工程与建设，2014.28（3）:379-382.[3] 钱归.广明高速公路广州段软基处理方案及检测分析.华南理工大学硕士学位论文，2012.[4] 史慧杰.强夯施工振动监测与夯后地基处理效果振动测试研究.中国海洋大学硕士学位论文，2005.Study on detection method of ground treatment effect

Huang Longyang Abstract:with the implementation of the various construction projects in China, due to thegeological characteristics of the various venues, often need to to deal with the foundation reinforcement, and the reinforcement treatment methods are different, difference between the effect of greatly.Thus, looking for effective ground treatment testing method is particularly important.In this paper, the current engineering application more foundation proceing detection technology are discued and summarized.Keywords: foundation treatment, effect, detection method Preface

With the rapid development of economy and technology in China, various construction projects started, but usually because of the particularity of geological conditions, the need for the construction site of the foundation reinforcement.The current application in the actual construction proce of the foundation treatment method, preloading, dynamic compaction, reinforcement method, the replacement method vibroflotation, pile, jet grouting pile, soil improvement, but often due to human factors foundation treatment method of limitations and in the proce of construction, resulting in uneven ground treatment effect.But a qualified engineering foundation, is an important guarantee for building design, construction quality and safety and therefore play an increasingly important role the detection effect of detection of reinforcement foundation.In current engineering application method in foundation detection proceing are the main load test, dynamic penetration test, cone penetration test, ten plate shear test, wave velocity Test, core test and so on, but all kinds of test methods are limited in their own conditions, the accuracy of the test is very large.This paper combined with some engineering examples, the application and effect of these testing methods are discued.2Test research on effect of foundation treatment

At present, many scholars have done a variety of research on the effect of the foundation reinforcement treatment, and discued the advantages and disadvantages of various methods, this paper will be used in the following projects to elaborate and sum up.2.1 Static load test of foundation

Based on static load test is a kind of high precision, analysis the result is consistent with the actual well test method, the foundation bearing capacity determination and foundation settlement calculation is relatively accurate, but the cost is high, the strict technical requirements and test cycle is relatively long, generally large project site survey are required to perform the test.2.1.1 Static load test

Static load test simulation of foundation soil for buildings load conditions, loading on rigid bearing plate, uniform load transfer to the ground through the bearing plate, the deformation characteristics of Foundation Soil Determination of natural burial conditions, so as to ae the bearing capacity of foundation soil, settlement calculation of soil deformation modulus and deformation characteristics can be estimated based.The soil foundation reflects the more intuitive.The method for determining the bearing capacity of the foundation is: when the preure ratio limit final settlement curve, the load ratio limit value corresponding to the load limit;when the load is le than 2 times the value of the corresponding proportion limit, half limit load value;when cannot be determined according to the above two requirements, desirable load s/b=0.01 corresponding, but its value should not exceed the maximum loading amount of half(Qian Gui.2012).2.1.2 Static load test evaluation Wang Wenkui(Wang Wenkui.2014), the I-steel and stacking preure counter preure system, with preure platform force method is used to test the quality of a wharf along the Yangtze River land foundation treatment engineering.Square plate preloading foundation loading plate to the side of 1m, because of the engineering site foundation treatment design bearing capacity characteristic value is 120kPa, so the test of maximum load is 2 times the design value is 240kpa, according to 24kpa each stage of loading, and the settlement observation in the loading proce, determine the characteristic value of bearing capacity of foundation.The test were tested in 20, the P-S curve can be seen, when the maximum load to 240kpa, all the measurement points are did not reach the limit state, the maximum settlement is 8.400mm, the minimum settlement is 6.200mm, according to the selection principle of the characteristic value of bearing capacity, half maximum load, which is 240kpa/2=120kpa to the point after the treatment of the foundation bearing force characteristic value, all The bearing capacity of the measuring point is satisfied with the design requirements.The project adopts the static load test to evaluate the foundation treatment, and shows that the ground treatment of the site has reached the foundation bearing capacity of the ground design 120kpa.2.2 vane shear test

Due to its own limitations, the vane shear test is generally used in the coastal areas of soft soil sites, and in some of the gravel soil can not be used to conduct the evaluation of the effect of ground treatment.2.2.1Brief introduction ofvane shear test Test, inverse clockwise rocking torsion box device small cranks, every 10 seconds to rotate one degree at a constant rate of rotation, when the test to peak or stable value, to test for 1min, test data, such as normal and record the peak data.According to the numerical calculation of undisturbed soil shear strength;complete shear strength determination, along the reverse direction continuous rotation of the probe rod coil 6, in accordance with the above steps operation, the determination of remolded soil undrained shear strength.2.2.2 cro plate shear test evaluation examples summary Wang Wenkui(Wang Wenkui.2014)Adopting vane shear test of along the Yangtze River a wharf land foundation treatment engineering quality detection.The experiment a total of eight holes, each hole 18 measuring points, on each hole detection data statistics, through with the original geological survey data are compared, the soil shear strength has been greatly improved, foundation treatment reached expected effect.2.3 light penetration test N10 light dynamic penetrometer for light penetration, their quality is light, simple equipment, widely used, easy operation, low cost and in a wide range of application in soft soil area.2.3.1Thelight penetration test The hammer blow energy, with probe, and the probe rod into the soil, according to the degree of difficulty of the penetration to evaluate soil properties, mainly used for grain filling and gravelly soil layer, and can be used for continuous penetration, in the test depth range continually measured soil mechanical properties and change rules(Qian Gui.2012).2.3.2 light penetration test evaluation summary Wang Wenkui et al.(Shi Huijie.2013)the light dynamic penetration test of along the Yangtze River a wharf land foundation treatment engineering quality detection.Site of 56 cement mixing pile top under the 2m range of pile head were measured.The experimental results show that the pile top under 2m every 30cm hammer hammer number is 64-78 hammer and design values: hammer N10>35 / cm2, uniform cement soil piles detection range, quality meet the design requirements.2.4 core test Core test is drilling and taking the foundation treatment of the foundation soil, and then carry out laboratory tests, in order to evaluate the effect of the foundation treatment, in some large-scale projects are more common.2.4.1 core test The application of jet grouting pile, vibro pile, mixing pile of foundation soil treatment site, on foundation pile core test, its purpose is mainly testing the quality of pile body concrete situation in, check the pile body concrete bonding conditions, stomatal, loose or broken pile;check the pile bearing stratum at the bottom of the geotechnical properties and thickne meets design requirement or standard, and check the construction record of pile length is real.2.4.2 core test case summary Wang Wenkui(Shi Huijie.2013)by taking the core test along the Yangtze River a wharf land foundation treatment engineering quality testing, completed a total of 16 cement mixing pile testing, core test and unconfined compreive strength group, 48, pile core sample molding average length of 8.5m, forming section of the core sample into short columnar fracture are in good agreement, pile body 8.30m post and core sample is not formed, has not formed the strength.Strength of core sample: completed a total of strength test group(n = 48, no side limit compreion strength average value for 3.1mpa.Qian Gui(Qian Gui.2012)of Guangming Expreway Guangzhou section of soft foundation treatment of subgrade detecting core to check, the cores taken rate of close to 100%, the take rate 65.4%-74.4%.core sample continuous, complete, well cemented, a long column, concrete pile compreive strength represents value for 22.1Mpa that the soft soil foundation treatment to the foundation treatment design requirements.2.5 wave velocity test Wave velocity test is one of the common methods of foundation treatment, its equipment is simple, operation is simple, the price is relatively low, the scope of application is wider.2.5.1 core test Produced on the ground vertical shock, will in the near the surface of the layered continuous medium in which the Rayleigh wave, which is characterized by high energy and propagation speed is low, the low frequency with time attenuation is slow and easy to identify.In layered medium, Rayleigh wave method with dispersion characteristics in the same area for a series of frequency of the Rayleigh wave velocity can be obtained by a Rayleigh wave dispersion curves, different wavelength of Rayleigh wave propagation characteristics reflect the different depth of rock and soil medium kinematics characteristics, the dispersion curve inversion of underground velocity interface layer thickne and velocity structure, to determine each layer of rock and soil ma velocity and depth parameter.2.5.2 core test case summary Hui Jie Shi(Wang Wenkui.2014)on the West Bay of Qingdao Beihai made ship repairing base of sea reclamation area after foundation treatment by the Rayleigh wave test, the test curve reflects the surface filling stone compactne is not uniform, changes in the larger, 6.2 m below the wave velocity increases gradually, to 11.2 M wave velocity decreases, indicating that the with depth increasing, fill stone density also increases, but to 11.2 m below the velocity suddenly becomes small, reflecting the 1.2m in the mixed layer;12m-12.9m curve linear, constant velocity, reflect the 12m-12.9m into the silt layer;following 12.9 M wave velocity increases rapidly to 452.5m/s, that 12.9 m after entering the weathered bedrock.Drilling results and surface wave test results are basically the same.Existing problems Because the site itself is complex and changeable, foundation treatment proce due to the method of selection of the different construction proce of human factors influence, will cause the great difference, therefore on the foundation treatment effect detection is particularly important.But in actual operation proce, due to the limitations and the subsurface complexity of various methods, so often need to more comprehensive method of use, to achieve the goal of mutual authentication.At the same time, it also requires us to constantly explore, the existing methods are perfect and looking for new and more effective technical means

References

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