特哈马不同含泥量风积沙路基填料特性试验研究
发布时间：2018-07-16 21:35
【摘要】：土木工程项目的施工与维护取决于场地、周围环境和气候的变化。风积沙地区的公路、铁路和基础设施设计、施工和维修都会存在特有的问题,例如:防沙、固沙、防风等。由于人口、经济和其它因素的作用,在沙漠或沙漠化地区修建基础设施是未来趋势。各地沙漠的形成环境、气候及风沙条件有差异,地质、风积沙特性以及地表植被状况也有较大差别。遍布该地区的风积沙地基是否需要处理、能否用作路基填料,都是需要进行试验研究的技术问题,以便更好理解其工程特性,提出合理的解决方法。也门共和国需要在沙漠地区修建公路,不可避免会遇到风积沙作为路基填料的问题。2003年修建的总长170km的荷台达—摩卡高速公路,沿着红海海岸线走向,穿越广阔的沙土地带,这意味着必需要用这种沙土作为路基填料。荷台达位于也门西海岸中部卡希布湾内,沿红海海岸向东延伸至山脚下,海拔从海平面上升至250m。北纬15.8-13.38,东经43.38-42.35,总面积约13336平方公里,是也门重要的农业生产区。该地区属热带沙漠气候,盛行西南风。年平均气温19~40摄氏度。8~9月份常出现强风及沙暴。全年平均降雨量达100mm。荷台达海岸平原地基土是第四纪冲积土,包括风积土和冲积土。风积沙土经过处理可以作为路基填料,这就需要试验研究来解决这类工程技术问题。当前,需要对不同含泥率的风积沙土特性进行试验研究。本文参考国内外研究成果,结合荷台达—摩卡公路,对不同含泥率的风积沙土特性进行系统的试验研究。主要研究内容及技术路线如下:(1)利用室内试验,研究了不同含泥量的风积沙物理特性,对不同含泥量的风积沙工程地质特性进行评价。(2)对不同含泥量风积沙进行压实试验,研究不同含泥量风积沙压实特性,分析其压实机理。(3)通过一系列强度和压缩试验研究,探索了不同含泥量风积沙强度特性和变形特性,研究了不同含泥量风积沙的强度特性和变形特性的影响因素及作用机理。(4)研究总结不同含沙量风积沙的力学特性,提出不同含泥量风积沙的力学指标变化范围,并提出不同含泥量风积沙最大干密度的试验方法。(5)根据试验结果,对不同含泥量风积沙路用性能进行综合评价,确定出适合作为路基填料的最佳含泥量范围。结合室内试验研究结果,深入分析不同含沙量风积沙的物理特性、压实性、强度特性和变形特性,综合评价了不同含沙量风积沙作为路基填料的工程特性,提出了合适的含沙量范围。具体研究成果如下:1.不同含泥量的风积沙的物理特性试验研究通过颗粒级配试验可发现,荷台达—摩卡高速公路含泥风积沙的粒径主要分布在0.6~0.074mm范围内,属于中细沙;各沙样的不均匀系数Cu显示,荷台达—摩卡高速公路含泥风积沙的不均匀系数均较小,说明颗粒级配不良,粒度均比较均匀。为了研究荷台达—摩卡高速公路不同含泥量风积沙的工程特性,制备不同含泥量(0.074mm)的风积沙试样,制备了含泥量分别为0.5%,5%,10%,50%,55%和80%7种试样。不均匀系数Cu反映的是大小不同粒组分布情况。Cu越大表明土粒粒径的分布范围越大,其级配就越良好,作为路基填料时,则较容易得到较大的密实度。曲率Cc表明的是粒径累积曲线的分布范围,反映了曲线的整体形状。一般认为:当土样同时满足Cu5和Cc=l~3两个条件时,则属于级配良好。级配试验结果显示:不同含泥量风积沙的不均匀系数Cu大多小于5,只有含泥量为0.5%时,其不均匀系数Cu=5.13;所有试样的曲率系数Cc均在1~3之间,由此可见,大部分的风积沙试样级配不良。采用比重瓶法对不同含泥量风积沙试样进行比重试验。试验结果表明:随着试样含泥量的增大,试样土粒比重也是逐渐增大的。土的界限含水量是指土的液限和塑限,土的液限和塑限主要是用于划分土类、及公路设计和施工中。本文采用联合测定法测定所有试样的液限和塑限。对于含泥量较小的试样(含泥量4.5%),由于细颗粒土含量少,可以不考虑其液限和塑限。试验结果表明:随着试样中含泥量的增加,试样的液限、塑限以及塑性指数均在增大,这是由于随着粘性含量的增加,试样中矿物成分发生变化,含泥量变化时土颗粒之间吸附水膜厚度也在变化。由于含泥风积沙所在地区的差异性,其天然干密度也不尽相同。荷台达平原不同含泥量风积沙干密度一般在1.56~1.84g/cm3。尽管含泥风积沙经常处于干旱状态下,但其天然含水量一般要比纯净风积沙的较高。天然含水量低的地方,含泥风积沙含水量可以不足1%,天然含水量高的地方,含泥风积沙含水量也不会超过10%。随着季节的变化,含泥风积沙里的含水量也会不断变化,变化范围与含泥量有关,如在春季含水量变化幅度为0.2%~4%,在夏季仅为0.1%~1%。由于蒸发作用,沙漠表层的含水量小,越往下含水量逐渐增大。含泥风积沙里少量的水分,对于该地区的植物生长却有重要的作用。在降雨量小的地区,含泥风积沙的含水量会更低。荷台达—摩卡高速公路含泥风积沙由于含有一定含量的细粒土,故具有一定的塑性特性,根据含泥量的不同,各种风积沙表现出的塑性程度也不一样。含泥量小的试样,塑性低,试样成型困难,且抗剪强度低。荷台达—摩卡高速公路含泥风积沙基本上具有亲水性,即颗粒表面对水有一定的吸附作用,随着含泥量的增加,亲水性越来越强烈。含泥量较小时,风积沙的渗透性较好,地面水会很快渗入地层深处,导致地层表层土常处于干燥状态。对于荷台达—摩卡高速公路含泥风积沙,在含泥量较小时,均不具有湿陷性。含泥量不同,风积沙中的毛细水对路基工程的不利影响程度也不同。因为含泥风积沙的毛细现象主要与孔隙比、含泥量、结合水膜、沙粒的有效粒径和形状等有关。含泥量越大,细颗粒越多,比表面积越大,颗粒表面亲水性强,毛细现象越强烈。2.含泥风积沙压实特性试验研究为了研究荷台达—摩卡高速公路含泥风积沙压实特性,本文采用重型标准击实试验、干振法和水振法三种不同方法,对不同含泥量内积怨沙试样进行压实试验。重型标准击实试验结果表明:含泥量在0.56%~9.2%范围内,最大干密度在干燥状态下出现,随着含水量增大,干密度呈下降趋势;含泥量在9.2%~51.31%范围内,击实曲线呈不规则变化,忽上忽下,干密度总体比含泥量小的风积沙要小;当含泥量大于55.89%时,击实曲线与细粒土的类似,即含水量小于最优含水量时,干密度随着含水量的增加而增大。含泥风积沙最大干密度的变化趋势是,随着含泥量的增加,最大干密度呈减小趋势。干振法试验结果显示:含泥量小于51.31%的风积沙试样表现为类似于风积沙振动性质,在一定的时间和振幅下,干密度随时间增大,振动时间大约在4~8分钟内,试样达到最大干密度,之后,干密度随振动时间减小;含泥量大于51.31%时,含泥风积沙干密度随振动时间一直减小,且干密度较含泥量小于51.31%风积沙的小很多;当含泥量大于55.87%时,干密度下降更明显,这也说明振动法不适用于细粒土。含泥量为9.2%时,风积沙最大干密度最大,之后,随含泥量增加,风积沙最大干密度减小。水振法试验结果表明:含泥量小于51.31%时,干密度在4~8分钟内达到最大值,且含泥量越小干密度总体越大;含泥量大于51.31%时,试样的干密度整体上小于含泥量小于51.31%试样的;含泥量小于4.5%时,利用水振法风积沙可以得到较大的干密度;水振法试验得到的风积沙最大干密度随含泥量的增大而减小。比较三种试验结果发现:采用重型击实方法时,在含泥量较小时,风积沙最大干密度随含泥量增加而减小,在含泥量为20%~30%范围内,风积沙最大干密度基本保持稳定值不变,含泥量大于30%时,风积沙最大干密度随含泥量增加继续减小。采用干振法时,最大干密度在含泥量为0.56%出现最大值,直到含泥量增加至30%左右,最大干密度随含泥量变化不明显,当含泥量大于30%时,最大干密度随含泥量增加而减小。水振法试验得到的含泥风积沙最大干密度与含泥量变化规律与重型标准击实试验类似,只是当含泥量小于30%时,水振法得到的最大干密度比重型标准击实试验得到的略大一点,当含泥量大于30%时,水振法得到的最大干密度随含泥量的增加而减小得更明显。当含泥量小于30%时,水振法得到的最大干密度最大,干振法得到的最小,当含泥量大于30%时,重型标准击实试验得到的最大干密度最大,水振法得到的最小。可见,不同含泥量的风积沙,应采用不同的击实方法来获得更大的干密度。3.含泥风积沙的强度特性试验研究本文采用直剪试验、回弹试验和CBR试验研究不同压实度、不同含泥量下含泥风积沙的强度特性。分析直剪试验结果得出:荷台达—摩卡高速公路含泥风积沙内摩擦角在30°~40°之间,内摩擦角与压实度近似呈线性关系,通过回归分析,相关系数均在0.9以上,且内摩擦角随压实度的增大而增加。对于含泥量小于9.2%的风积沙,其内摩擦角整体上均大于含泥量大于51.31%的风积沙的,含泥量为9.2%时内摩擦角出现最大值。含泥量大于51.31%时,风积沙内摩擦角随含泥量增加而减小。含泥风积沙粘聚力均较小,且随含泥量减小而减小。压实度对含泥风积沙的内摩擦角影响明显,内摩擦角随压实度增大而增加;在含泥量小于10%左右时,内摩擦角随含泥量增大而增加,含泥量大于10%时,内摩擦角随含泥量增大而减小。回弹试验结果表明:含量泥风积沙的回弹模量在40MPa~65MPa之间;含泥量小于9.2%时,回弹模量与压实度近似呈三次多项式函数关系,回弹模量随压实度增加;当含泥量大于51.31%时,回弹模量与压实度近似呈二次多项式函数关系,回弹模量仍随压实度增加。在压实度不变的前提下,回弹模量与含量泥量有一定的关系,含泥量小于9.2%时,回弹模量大小较接近,此时含泥量对回弹模量影响不明显,在含泥量为9.2%时,回弹模量整体达到最大,含泥量在51.31%~84.13%范围内时,回弹模量随含泥量增大而减小。压实度对含泥风积沙回弹模量影响显著,在每个压实度下,回弹模量大约在含泥量为10%时达到最大值,含量泥量小于10%时,回弹模量随含泥量增加而增大,含泥量大于10%时,回弹模量随含泥量增加而减小,含泥量达到55%左右时,回弹模量趋于稳定。CBR试验结果表明:含泥量小于9.2%时,CBR与含水量曲线存在峰值,即CBR值先随含水量的增加而增大,CBR达到最大值时,又随含水量的增加而减小,含泥量在51.31%~84.31%范围内时,CBR基本随含水量增加而增大,但不明显。CBR最大值对应的含水量随含泥量增加而增大,含泥量为0.56%时,其对应的含水量为8%,含泥量为84.31时,其对应的含水量为15%左右。在含水量为8%,10%和12%三种情况下,对于含泥量小于9.2%的试样,浸水和不浸水的CBR值先随含泥量增大而减小,在含泥量为4.5%时达到最小值,之后CBR又随含泥量增大;含泥量大于9.2%时,浸水和不浸水试样的CBR值均随含泥量增加而减小,在含泥量达到55%左右时,两种试样的CBR值均趋于稳定;同一含泥量下,不浸水试样的CBR值大于浸水试样的。4.含泥风积沙的变形特性试验研究采用固结压缩试验研究含泥风积沙特性。试验结果表明:孔隙比并不是随含泥量的增大一直增大的,含泥量在4.5%~9.2%之间时,孔隙比随含泥量增大而减小,含泥量在51.31~84.31%范围内时,孔隙比随含泥增加而增大,且孔隙比整体较大;整体孔隙比在含泥量为0.56%时最小,此时压缩系数也最小;在不同压实度下,随着试样含泥量的增加,压缩系数先减小至最小值,之后随含泥量逐渐增大;含泥量在10%左右时,压缩系数达到最小值,沁含泥量大于55.31%时,压缩系数随含泥量的增加更明显。5.含泥风积沙路用性能评价根据击实试验、直剪试验、回弹模量试验、CBR试验和压缩试验结果,分析得出荷台达—摩卡高速公路含泥风积沙大致可分为三类:(1)风积沙,含泥量小于9.2%;(2)沙、土混合,含泥量在9.2%~55.31%之间;(3)含沙质土,含泥量大于55.31%。如果以回弹模量和CBR作为评价指标,含量泥量小于9.2%风积沙均能满足高速公路路床、路堤部位填料的要求;对于含泥量大于9.2%的风积沙,可以采用物理改良方法,即往里掺入一定量的纯风积沙,降低其含泥量,使其达到路基填料的要求。
[Abstract]:The construction and maintenance of civil engineering projects depend on the site, environment and climate change. The road, railway and infrastructure design, construction and maintenance in the aeolian sand area will have special problems, such as sand prevention, sand fixation, wind protection, and the construction of infrastructure in desert or desertification areas due to the effect of population, economy and other factors. It is a trend in the future. There are differences in the forming environment of desert, climate and wind and sand conditions, geology, the characteristics of aeolian sand and the condition of surface vegetation. Whether the foundation of aeolian sand is needed to be treated and whether it can be used as a subgrade filler is a technical problem that needs to be tested and studied so as to better understand its engineering characteristics. The Yemen Republic needs to build a road in the desert area. It is inevitable that the wind and sand is inevitably encountered as a subgrade filler. The Hodeidah Mocha expressway, which was built in.2003, was built along the Red Sea coastline and across the broad sandy land, which means that this sand soil must be used as the road. Base filling. Hodeidah is located in the central Kaci Bay of the west coast of Yemen, extending eastward along the Red Sea coast to the foot of the mountain. The elevation rises from sea level to 250m. north latitude 15.8-13.38. It is an important agricultural production area in Yemen. It is an important agricultural production area in Yemen. The region is a tropical desert climate, and the southwest wind is prevalent. The annual average temperature is 19~4 Strong winds and sandstorms are often found at 0 degrees Celsius in.8~9 months. The average annual rainfall amount to 100mm. Hodeidah coastal plain is quaternary alluvial soil, including aeolian soil and alluvial soil. Aeolian sandy soil can be used as subgrade filler. This requires experimental research to solve such engineering problems. In this paper, the characteristics of sandy soil are studied. In this paper, the characteristics of aeolian sandy soil with different mud content are systematically tested and studied in combination with the Hodeidah Mocha highway. The main research contents and technical routes are as follows: (1) the physical characteristics of the aeolian sand with different mud content are studied by the laboratory test, and the different mud content of the sand is studied. The engineering geological characteristics of aeolian sand are evaluated. (2) the compaction test of aeolian sand with different mud content is carried out to study the compaction characteristics of the aeolian sand with different mud content and analyze its compaction mechanism. (3) through a series of strength and compression tests, the strength and deformation characteristics of the aeolian sand with different mud content are explored, and the aeolian sand with different mud content is studied. The influence factors and action mechanism of strength and deformation characteristics. (4) study and summarize the mechanical characteristics of aeolian sand with different sediment content, put forward the variation range of the mechanical indexes of different sediment laden wind sand, and put forward the test method of the maximum dry density of different slime. (5) according to the experimental results, the performance of the sand road with different mud content in aeolian sand is introduced. According to the results of laboratory tests, the physical characteristics, compactness, strength characteristics and deformation characteristics of different sand containing aeolian sand are thoroughly analyzed. The engineering characteristics of different sand content aeolian sand as road base fill are evaluated and the suitable sand content model is put forward. The specific research results are as follows: 1. the experimental study on the physical characteristics of the aeolian sand with different mud content can be found through the particle gradation test. The particle size of the mud aeolian sand in the Hodeidah Mocha expressway is mainly distributed in the range of 0.6~0.074mm, which belongs to medium fine sand; the non uniform coefficient Cu of each sand sample shows that the Hodeidah Mocha freeway contains mud. The unevenness coefficient of aeolian sand is small, indicating that the grain gradation is bad and the granularity is uniform. In order to study the engineering characteristics of the different mud content aeolian sand in Hodeidah Mocha expressway, the samples of the aeolian sand with different mud content (0.074mm) were prepared, and the mud content of the samples was 0.5%, 5%, 10%, 50%, 55% and 80%7, respectively. The non uniform coefficient was Cu inverse. The larger the distribution of different size group.Cu shows, the larger the distribution range of the soil particle size is, the better its gradation is, the greater the larger compactness is obtained when it is used as the subgrade filler. The curvature Cc shows the distribution range of the grain size accumulation curve and reflects the overall shape of the curve. Generally, it is considered that the soil sample satisfies both Cu5 and Cc=l~ at the same time. 3 and two conditions, the gradation is good. The result of gradation test shows that the unevenness coefficient Cu of different mud content aeolian sand is mostly less than 5, only when the mud content is 0.5%, the unevenness coefficient is Cu=5.13, and the curvature coefficient Cc of all samples is between 1~3, so it can be seen that most of the aeolian sand samples are not graded. The test results show that the specific gravity of the sample increases gradually with the increase of the mud content of the sample. The boundary water content of the soil is the liquid limit and the plastic limit of the soil. The liquid limit and the plastic limit of the soil are mainly used in the classification of soil, and in the design and construction of the highway. The liquid limit and plastic limit of the sample. For the sample with small mud content (4.5%), the liquid limit and plastic limit can be ignored because of the small size of the fine particle soil. The test results show that the liquid limit, plastic limit and plastic index of the sample increase with the increase of mud content in the sample, which is due to the increase of the viscosity. The thickness of the adsorbed water film between the soil particles is also changing when the mud content changes. The natural dry density of the slime in the Hodeidah plain is not the same. The dry density of the aeolian sand in the Hodeidah plain is generally in the dry state, but its natural water content is in the dry state. In the place where the natural water content is low, where the water content of the slime wind and sand can be less than 1% and the natural water content is high, the water content of the slime aeolian sand will not exceed the change of the 10%., and the water content in the sand containing the mud will also change continuously, the range of change is related to the mud content, such as water cut in spring. The amplitude of the change is 0.2%~4%. In the summer, the water content in the surface of the desert is small and the lower water content in the desert is gradually increasing. A small amount of water in the sand and sand is important to the growth of the plants in the area. The water content of the sand in the area with small rainfall will be lower. The Hodeidah Mocha high speed area will be lower. The mud aeolian sand in the highway has certain plastic properties because of a certain content of fine grained soil. According to the different mud content, the plastic degree of all kinds of aeolian sand is different. The sample with small mud content is low in plasticity and difficult to form, and the shear strength is low. The mud aeolian sand in Hodeidah Mocha expressway is basically related to the mud. Water, that is, the surface of the particle has a certain adsorption effect on water. With the increase of mud content, the hydrophilicity is becoming more and more intense. The permeability of the aeolian sand is better, the surface water will permeate into the depth of the stratum quickly, and the surface soil is often in the dry state. The mud content of the Hodeidah Mocha freeway is more mud than the mud. The amount of capillary water in aeolian sand is also different, because the capillary phenomenon in the aeolian sand is mainly related to the pore ratio, the mud content, the water film, the effective particle size and shape of the sand. The larger the mud content, the more fine particles, the larger the surface area, the relative surface of particles are relative. In order to study the compaction characteristics of mud aeolian sand in Hodeidah Mocha expressway, the compaction characteristics of.2. containing mud wind sand are stronger and stronger. In this paper, three different methods of heavy standard compaction test, dry vibration method and water vibration method are used in this paper. The results show that the maximum dry density appears in the dry state within the range of 0.56%~9.2%, and the dry density decreases with the increase of water content, and the compaction curve is irregular in the range of 9.2%~51.31%, and the dry density is smaller than the mud content, and the compaction curve when the mud content is more than 55.89%. Similar to fine soil, that is, when water content is less than the optimal water content, the dry density increases with the increase of water content. The maximum dry density of the sand containing aeolian sand decreases with the increase of mud content. The dry vibration test results show that the sample of aeolian sand containing less than 51.31% mud is similar to the wind product. Under certain time and amplitude, the dry density of sand is increased with time, the vibration time is about 4~8 minutes, the sample reaches the maximum dry density, and then the dry density decreases with the vibration time. When the mud content is more than 51.31%, the dry density of the slime is smaller with the vibration time, and the dry density is less than the 51.31% aeolian sand. The dry density decreases more obviously when the mud content is greater than 55.87%, which also indicates that the vibration method does not apply to the fine-grained soil. The maximum dry density of the aeolian sand is maximum when the mud content is 9.2%, and then the maximum dry density of the aeolian sand decreases with the increase of mud content. The results of water vibration test show that the dry density is reached within 4~8 minutes when the mud content is less than 51.31%. The larger the dry density is, the smaller the mud content is, the larger the dry density is, the dry density of the sample is less than 51.31% when the mud content is greater than 51.31%. When the mud content is less than 4.5%, the dry density can be obtained by the water vibration method, and the maximum dry density of the aeolian sand obtained by the water vibration method decreases with the increase of the mud content. The results of three tests showed that the maximum dry density of aeolian sand decreased with the increase of mud content when the mud content was less than the mud content. The maximum dry density of aeolian sand remained unchanged at 20%~30% range. The maximum dry density of aeolian sand continued to decrease with the increase of mud content when the mud content was more than 30%. When the dry vibration method is used, the maximum dry density is maximum at the mud content of 0.56% until the mud content increases to about 30%. The maximum dry density is not obvious with the mud content. When the mud content is more than 30%, the maximum dry density decreases with the increase of mud content. The maximum dry density and the mud content change law and the heavy standard of the slime in the water vibration test are obtained. The quasi compaction test is similar, but when the mud content is less than 30%, the maximum dry density ratio standard compaction test obtained by the water vibration method is slightly larger. When the mud content is more than 30%, the maximum dry density obtained by the water vibration method decreases more obviously with the increase of mud content. When the mud content is less than 30%, the maximum dry density obtained by the water vibration method is the most. The maximum dry density is the smallest. When the mud content is more than 30%, the maximum dry density of the heavy standard compaction test is the largest and the water vibration method is the least. The results of the direct shear test show that the friction angle of the inner friction angle of the Hodeidah to Mocha expressway is approximately 30 ~40 degrees, the internal friction angle and the degree of compaction are approximately linear, and the correlation coefficient is above 0.9, and the correlation coefficient is above and within. The friction angle increases with the increase of the degree of compaction. For the aeolian sand with mud content less than 9.2%, the internal friction angle is larger than that of the aeolian sand with mud content greater than 51.31%, and the internal friction angle is maximum when the mud content is 9.2%. When the mud content is more than 51.31%, the inner friction angle of the aeolian sand decreases with the increase of the mud content. The internal friction angle increases with the degree of compaction. When the mud content is less than 10%, the internal friction angle increases with the mud content and the mud content is greater than 10%. The internal friction angle decreases with the increase of mud content. The rebound test results show that the content of mud is the content of mud. The resilient modulus of aeolian sand is between 40MPa~65MPa. When the clay content is less than 9.2%, the modulus of resilience and the degree of compaction are approximately three times polynomial functions.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414;U416.1
本文编号：2127729
[Abstract]:The construction and maintenance of civil engineering projects depend on the site, environment and climate change. The road, railway and infrastructure design, construction and maintenance in the aeolian sand area will have special problems, such as sand prevention, sand fixation, wind protection, and the construction of infrastructure in desert or desertification areas due to the effect of population, economy and other factors. It is a trend in the future. There are differences in the forming environment of desert, climate and wind and sand conditions, geology, the characteristics of aeolian sand and the condition of surface vegetation. Whether the foundation of aeolian sand is needed to be treated and whether it can be used as a subgrade filler is a technical problem that needs to be tested and studied so as to better understand its engineering characteristics. The Yemen Republic needs to build a road in the desert area. It is inevitable that the wind and sand is inevitably encountered as a subgrade filler. The Hodeidah Mocha expressway, which was built in.2003, was built along the Red Sea coastline and across the broad sandy land, which means that this sand soil must be used as the road. Base filling. Hodeidah is located in the central Kaci Bay of the west coast of Yemen, extending eastward along the Red Sea coast to the foot of the mountain. The elevation rises from sea level to 250m. north latitude 15.8-13.38. It is an important agricultural production area in Yemen. It is an important agricultural production area in Yemen. The region is a tropical desert climate, and the southwest wind is prevalent. The annual average temperature is 19~4 Strong winds and sandstorms are often found at 0 degrees Celsius in.8~9 months. The average annual rainfall amount to 100mm. Hodeidah coastal plain is quaternary alluvial soil, including aeolian soil and alluvial soil. Aeolian sandy soil can be used as subgrade filler. This requires experimental research to solve such engineering problems. In this paper, the characteristics of sandy soil are studied. In this paper, the characteristics of aeolian sandy soil with different mud content are systematically tested and studied in combination with the Hodeidah Mocha highway. The main research contents and technical routes are as follows: (1) the physical characteristics of the aeolian sand with different mud content are studied by the laboratory test, and the different mud content of the sand is studied. The engineering geological characteristics of aeolian sand are evaluated. (2) the compaction test of aeolian sand with different mud content is carried out to study the compaction characteristics of the aeolian sand with different mud content and analyze its compaction mechanism. (3) through a series of strength and compression tests, the strength and deformation characteristics of the aeolian sand with different mud content are explored, and the aeolian sand with different mud content is studied. The influence factors and action mechanism of strength and deformation characteristics. (4) study and summarize the mechanical characteristics of aeolian sand with different sediment content, put forward the variation range of the mechanical indexes of different sediment laden wind sand, and put forward the test method of the maximum dry density of different slime. (5) according to the experimental results, the performance of the sand road with different mud content in aeolian sand is introduced. According to the results of laboratory tests, the physical characteristics, compactness, strength characteristics and deformation characteristics of different sand containing aeolian sand are thoroughly analyzed. The engineering characteristics of different sand content aeolian sand as road base fill are evaluated and the suitable sand content model is put forward. The specific research results are as follows: 1. the experimental study on the physical characteristics of the aeolian sand with different mud content can be found through the particle gradation test. The particle size of the mud aeolian sand in the Hodeidah Mocha expressway is mainly distributed in the range of 0.6~0.074mm, which belongs to medium fine sand; the non uniform coefficient Cu of each sand sample shows that the Hodeidah Mocha freeway contains mud. The unevenness coefficient of aeolian sand is small, indicating that the grain gradation is bad and the granularity is uniform. In order to study the engineering characteristics of the different mud content aeolian sand in Hodeidah Mocha expressway, the samples of the aeolian sand with different mud content (0.074mm) were prepared, and the mud content of the samples was 0.5%, 5%, 10%, 50%, 55% and 80%7, respectively. The non uniform coefficient was Cu inverse. The larger the distribution of different size group.Cu shows, the larger the distribution range of the soil particle size is, the better its gradation is, the greater the larger compactness is obtained when it is used as the subgrade filler. The curvature Cc shows the distribution range of the grain size accumulation curve and reflects the overall shape of the curve. Generally, it is considered that the soil sample satisfies both Cu5 and Cc=l~ at the same time. 3 and two conditions, the gradation is good. The result of gradation test shows that the unevenness coefficient Cu of different mud content aeolian sand is mostly less than 5, only when the mud content is 0.5%, the unevenness coefficient is Cu=5.13, and the curvature coefficient Cc of all samples is between 1~3, so it can be seen that most of the aeolian sand samples are not graded. The test results show that the specific gravity of the sample increases gradually with the increase of the mud content of the sample. The boundary water content of the soil is the liquid limit and the plastic limit of the soil. The liquid limit and the plastic limit of the soil are mainly used in the classification of soil, and in the design and construction of the highway. The liquid limit and plastic limit of the sample. For the sample with small mud content (4.5%), the liquid limit and plastic limit can be ignored because of the small size of the fine particle soil. The test results show that the liquid limit, plastic limit and plastic index of the sample increase with the increase of mud content in the sample, which is due to the increase of the viscosity. The thickness of the adsorbed water film between the soil particles is also changing when the mud content changes. The natural dry density of the slime in the Hodeidah plain is not the same. The dry density of the aeolian sand in the Hodeidah plain is generally in the dry state, but its natural water content is in the dry state. In the place where the natural water content is low, where the water content of the slime wind and sand can be less than 1% and the natural water content is high, the water content of the slime aeolian sand will not exceed the change of the 10%., and the water content in the sand containing the mud will also change continuously, the range of change is related to the mud content, such as water cut in spring. The amplitude of the change is 0.2%~4%. In the summer, the water content in the surface of the desert is small and the lower water content in the desert is gradually increasing. A small amount of water in the sand and sand is important to the growth of the plants in the area. The water content of the sand in the area with small rainfall will be lower. The Hodeidah Mocha high speed area will be lower. The mud aeolian sand in the highway has certain plastic properties because of a certain content of fine grained soil. According to the different mud content, the plastic degree of all kinds of aeolian sand is different. The sample with small mud content is low in plasticity and difficult to form, and the shear strength is low. The mud aeolian sand in Hodeidah Mocha expressway is basically related to the mud. Water, that is, the surface of the particle has a certain adsorption effect on water. With the increase of mud content, the hydrophilicity is becoming more and more intense. The permeability of the aeolian sand is better, the surface water will permeate into the depth of the stratum quickly, and the surface soil is often in the dry state. The mud content of the Hodeidah Mocha freeway is more mud than the mud. The amount of capillary water in aeolian sand is also different, because the capillary phenomenon in the aeolian sand is mainly related to the pore ratio, the mud content, the water film, the effective particle size and shape of the sand. The larger the mud content, the more fine particles, the larger the surface area, the relative surface of particles are relative. In order to study the compaction characteristics of mud aeolian sand in Hodeidah Mocha expressway, the compaction characteristics of.2. containing mud wind sand are stronger and stronger. In this paper, three different methods of heavy standard compaction test, dry vibration method and water vibration method are used in this paper. The results show that the maximum dry density appears in the dry state within the range of 0.56%~9.2%, and the dry density decreases with the increase of water content, and the compaction curve is irregular in the range of 9.2%~51.31%, and the dry density is smaller than the mud content, and the compaction curve when the mud content is more than 55.89%. Similar to fine soil, that is, when water content is less than the optimal water content, the dry density increases with the increase of water content. The maximum dry density of the sand containing aeolian sand decreases with the increase of mud content. The dry vibration test results show that the sample of aeolian sand containing less than 51.31% mud is similar to the wind product. Under certain time and amplitude, the dry density of sand is increased with time, the vibration time is about 4~8 minutes, the sample reaches the maximum dry density, and then the dry density decreases with the vibration time. When the mud content is more than 51.31%, the dry density of the slime is smaller with the vibration time, and the dry density is less than the 51.31% aeolian sand. The dry density decreases more obviously when the mud content is greater than 55.87%, which also indicates that the vibration method does not apply to the fine-grained soil. The maximum dry density of the aeolian sand is maximum when the mud content is 9.2%, and then the maximum dry density of the aeolian sand decreases with the increase of mud content. The results of water vibration test show that the dry density is reached within 4~8 minutes when the mud content is less than 51.31%. The larger the dry density is, the smaller the mud content is, the larger the dry density is, the dry density of the sample is less than 51.31% when the mud content is greater than 51.31%. When the mud content is less than 4.5%, the dry density can be obtained by the water vibration method, and the maximum dry density of the aeolian sand obtained by the water vibration method decreases with the increase of the mud content. The results of three tests showed that the maximum dry density of aeolian sand decreased with the increase of mud content when the mud content was less than the mud content. The maximum dry density of aeolian sand remained unchanged at 20%~30% range. The maximum dry density of aeolian sand continued to decrease with the increase of mud content when the mud content was more than 30%. When the dry vibration method is used, the maximum dry density is maximum at the mud content of 0.56% until the mud content increases to about 30%. The maximum dry density is not obvious with the mud content. When the mud content is more than 30%, the maximum dry density decreases with the increase of mud content. The maximum dry density and the mud content change law and the heavy standard of the slime in the water vibration test are obtained. The quasi compaction test is similar, but when the mud content is less than 30%, the maximum dry density ratio standard compaction test obtained by the water vibration method is slightly larger. When the mud content is more than 30%, the maximum dry density obtained by the water vibration method decreases more obviously with the increase of mud content. When the mud content is less than 30%, the maximum dry density obtained by the water vibration method is the most. The maximum dry density is the smallest. When the mud content is more than 30%, the maximum dry density of the heavy standard compaction test is the largest and the water vibration method is the least. The results of the direct shear test show that the friction angle of the inner friction angle of the Hodeidah to Mocha expressway is approximately 30 ~40 degrees, the internal friction angle and the degree of compaction are approximately linear, and the correlation coefficient is above 0.9, and the correlation coefficient is above and within. The friction angle increases with the increase of the degree of compaction. For the aeolian sand with mud content less than 9.2%, the internal friction angle is larger than that of the aeolian sand with mud content greater than 51.31%, and the internal friction angle is maximum when the mud content is 9.2%. When the mud content is more than 51.31%, the inner friction angle of the aeolian sand decreases with the increase of the mud content. The internal friction angle increases with the degree of compaction. When the mud content is less than 10%, the internal friction angle increases with the mud content and the mud content is greater than 10%. The internal friction angle decreases with the increase of mud content. The rebound test results show that the content of mud is the content of mud. The resilient modulus of aeolian sand is between 40MPa~65MPa. When the clay content is less than 9.2%, the modulus of resilience and the degree of compaction are approximately three times polynomial functions.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414;U416.1
【共引文献】
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1 朱敏;陈文猛;;稻田冲压密实节水灌溉技术推广应用探讨[J];水利水电技术;2014年07期
，本文编号：2127729
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