本文選題：壓實(shí)黃土 + 擊實(shí)能�。� 參考：《太原理工大學(xué)》2014年博士論文

【摘要】：隨著改革開放和現(xiàn)代化建設(shè)的不斷推進(jìn),我國國民經(jīng)濟(jì)取得了長(zhǎng)足發(fā)展,社會(huì)化進(jìn)程不斷加快。然而建設(shè)規(guī)模的不斷擴(kuò)大、城市化進(jìn)程的加快與自然環(huán)境產(chǎn)生了不可避免的沖突,自然環(huán)境惡化、建設(shè)用地緊張的問題日益突出。開山填洼,人工造地的辦法很好地解決了建設(shè)用地緊張的問題。我國西北、華北等地多數(shù)位于黃土高原地帶,山多川少,特殊的地形地貌導(dǎo)致了在經(jīng)濟(jì)建設(shè)加快發(fā)展過程中大量填方工程的出現(xiàn),其中不乏高填方工程。此外,我國西北、華北又廣泛分布黃土。黃土工程性質(zhì)特殊,具有水敏性。因此,針對(duì)黃土狀填土的巖土工程問題逐漸凸顯。長(zhǎng)期以來,人們對(duì)原狀黃土各種工程性質(zhì)的研究已較為深入,但基于黃土狀填土的強(qiáng)度、變形或結(jié)構(gòu)方面的系統(tǒng)研究尚不多見。 未經(jīng)處理或處理不當(dāng)?shù)奶钔恋鼗?往往存在不均勻沉降或過大沉降等問題,從而引發(fā)上部建(構(gòu))筑物開裂、下沉等各種工程事故。壓實(shí)或強(qiáng)夯是目前處理填土地基最常用的手段,而填土的壓實(shí)質(zhì)量直接影響地基或路基的工程質(zhì)量,保證填土壓實(shí)質(zhì)量是保證回填地基或路基工程質(zhì)量的關(guān)鍵,也是保證上層建筑正常使用的重要環(huán)節(jié)。本文以國家自然科學(xué)基金項(xiàng)目“壓實(shí)黃土的強(qiáng)度與變形影響因素及其微觀結(jié)構(gòu)研究(51178287)”為依托,對(duì)取自山西呂梁和太原兩地的典型黃土作為填土材料的工程力學(xué)性質(zhì)進(jìn)行了分析研究,揭示了黃土的壓實(shí)特性以及壓實(shí)黃土強(qiáng)度、變形等變化規(guī)律受擊實(shí)含水量、擊實(shí)能以及浸水等因素的影響,結(jié)合微觀結(jié)構(gòu)分析,將內(nèi)、外因素相結(jié)合對(duì)壓實(shí)黃土及其受浸水影響表現(xiàn)的力學(xué)性質(zhì)進(jìn)行了合理的解釋。為進(jìn)一步深入認(rèn)識(shí)和把握壓實(shí)黃土的工程力學(xué)特性,正確評(píng)價(jià)壓實(shí)黃土的性狀及壓實(shí)質(zhì)量,有效開展黃土地區(qū)回填工程設(shè)計(jì)、施工質(zhì)量控制等提供相關(guān)的物理性質(zhì)指標(biāo)和參數(shù),具有一定的現(xiàn)實(shí)意義。主要成果整理如下： (1)壓實(shí)黃土試樣在不浸水時(shí)的各項(xiàng)強(qiáng)度指標(biāo)均隨擊實(shí)含水量增加而降低,壓縮變形隨擊實(shí)含水量增加而增大。不同含水量范圍內(nèi)壓實(shí)黃土的強(qiáng)度和變形隨擊實(shí)能增長(zhǎng)的變化規(guī)律不同,在最優(yōu)含水量干側(cè)壓實(shí)的土體,擁有較高的強(qiáng)度指標(biāo)和較低的壓縮性。但擊實(shí)的作用使得壓實(shí)黃土的結(jié)構(gòu)不同于原狀黃土,在較小含水量擊實(shí)下的土體更具親水性,從而造成遇水軟化、強(qiáng)度降低等現(xiàn)象。相對(duì)而言,在最優(yōu)含水量濕側(cè)壓實(shí)的土體受浸水的影響要小。 (2)多因素影響分析結(jié)果表明初始含水量對(duì)壓實(shí)黃土壓縮應(yīng)變的影響最大,而垂直壓力對(duì)抗剪強(qiáng)度的影響最大；單因素分析時(shí)擊實(shí)能的影響相對(duì)較小,但擊實(shí)能與含水量的交互作用對(duì)于壓實(shí)黃土壓縮變形和抗剪強(qiáng)度的影響都比較大。 (3)當(dāng)壓力不超過400kPa時(shí),壓實(shí)黃土的εs-P關(guān)系可用雙曲線模型擬合,但對(duì)于較大壓力范圍內(nèi)壓實(shí)黃土的εs-P關(guān)系采用冪函數(shù)模型擬合更符合實(shí)際。在冪函數(shù)擬合基礎(chǔ)上,提出了采用改進(jìn)的割線模量法計(jì)算填土地基沉降量公式,并結(jié)合工程實(shí)例進(jìn)行了驗(yàn)證。 (4)相同擊實(shí)能作用下,壓實(shí)黃土試樣的主應(yīng)力差-軸向應(yīng)變關(guān)系隨初始含水量的增加呈現(xiàn)由應(yīng)變軟化—弱應(yīng)變硬化—強(qiáng)應(yīng)變硬化的變化趨勢(shì)。可將最優(yōu)含水量作為區(qū)分壓實(shí)黃土試樣應(yīng)變軟化和應(yīng)變硬化的分界含水量。 (5)壓實(shí)黃土的微結(jié)構(gòu)類型為團(tuán)粒體結(jié)構(gòu),基本單元體以團(tuán)粒為主,孔隙主要包括團(tuán)粒間孔隙和團(tuán)粒內(nèi)孔隙兩種。相同擊實(shí)能作用下的壓實(shí)黃土其結(jié)構(gòu)形式隨初始含水量由小到大變化呈現(xiàn)由松散到密實(shí),由無序的粒間排列到有序的粒間排列,由各向同性到各向異性的變化過程。 (6)對(duì)于黃土這種對(duì)水具有特殊敏感性的典型細(xì)粒土,壓實(shí)過程中對(duì)其含水量的控制尤為重要。在保證壓實(shí)度達(dá)到要求的前提下,可同時(shí)采用空氣體積率作為黃土狀填土壓實(shí)質(zhì)量控制指標(biāo)。空氣體積率的控制標(biāo)準(zhǔn)應(yīng)結(jié)合具體壓實(shí)土樣的室內(nèi)擊實(shí)試驗(yàn)來制定,一般以不超過10%為佳。采用重型機(jī)械壓實(shí)時(shí),最好將黃土狀填土施工時(shí)的含水量控制在最優(yōu)含水量的濕側(cè)2%以內(nèi),這樣在滿足相應(yīng)的壓實(shí)標(biāo)準(zhǔn)前提下,既可使變形和強(qiáng)度指標(biāo)達(dá)到設(shè)計(jì)的要求,而且對(duì)于保證填土地基或路基的水穩(wěn)定性更為有利。
[Abstract]:With the continuous promotion of reform and opening up and modernization, China's national economy has made great progress and accelerated the process of socialization. However, the expansion of the scale of construction, the acceleration of the process of urbanization and the natural environment inevitably conflict with the natural environment, the problem of construction land tension is becoming more and more prominent. In the northwest, North China and other places, most of China's northwest, North China and other places are located in the Loess Plateau, and there are many mountains and few mountains. The special terrain and landforms have led to the emergence of a large number of fill projects in the process of accelerating economic development, among which there are no lack of high fill project. In addition, North China and North China are widely distributed yellow. The engineering properties of loess are special and have water sensitivity. Therefore, the geotechnical problems of the Loess Fill are gradually highlighted. For a long time, the research on the engineering properties of the original loess has been deeply studied, but the research on the strength, deformation and structure based on the Loess Fill is still rare.
Untreated or untreated fill subsoil often has problems such as uneven settlement or excessive settlement, which leads to a variety of engineering accidents, such as the cracking and sinking of the upper construction (construction). Compaction or dynamic compaction is the most commonly used means to deal with the fill subgrade. The compaction quality of the fill directly affects the quality of the foundation or subgrade, and guarantees the filling. The quality of soil compaction is the key to guarantee the quality of backfilling foundation or subgrade, and it is also an important link to ensure the normal use of superstructure. Based on the National Natural Science Foundation Project "the influence factors of compaction and deformation of compacted loess and its microstructure study (51178287)", the typical yellow from Lvliang and Taiyuan, Shanxi, is a typical Yellow River. The soil, as a filling material, has been analyzed and studied. The compaction characteristics of the loess, the intensity and the deformation of the compacted loess are influenced by the factors such as the water content, the compaction energy and the soaking water. Combined with the microstructure analysis, the effects of the internal and external factors on the compacted loess and the water affected by the soaking are combined. In order to further understand and grasp the engineering mechanical properties of compacted loess, correctly evaluate the properties of the compacted loess and the quality of compaction, effectively carry out the design of backfilling engineering in the loess region and the quality control of the construction, it is of certain practical significance. Collate as follows:
(1) the strength index of compacted loess decreases with the increase of compaction water content, and the compression deformation increases with the increase of compaction water content. The intensity and deformation of compacted loess in different water content range vary with the increase of compaction energy, and the soil which is compacted at the optimal water content has a higher strength. But the compaction effect makes the compacted loess structure different from the original loess, and the soil under the smaller water content is more hydrophilic, thus resulting in the softening of the water and the decrease of the strength. In contrast, the soil under the optimum moisture content and wet side is less affected by the water immersion.
(2) the results of multi factor analysis show that the initial water content has the greatest influence on compacted loess compression strain, while the vertical pressure has the greatest impact on the shear strength; the impact of the compaction energy is relatively small when the single factor analysis is analyzed, but the influence of the interaction of compaction and water content on the compression deformation and shear strength of the compacted yellow soil is relatively large.
(3) when the pressure is not more than 400kPa, the epsilon s-P relationship of the compacted loess can be fitted with a hyperbolic model, but the fitting of the power function model for the s-P relationship of the compacted loess in the larger pressure range is more practical. On the basis of the power function fitting, a formula for calculating the settlement of the soil foundation with an improved secant model quantity method is proposed and combined with the work. The process example is verified.
(4) under the action of the same compaction, the relationship between the main stress difference and the axial strain of the compacted loess samples with the increase of initial water content shows the changing trend of strain softening, weak strain hardening and strong strain hardening, and the optimal water content can be used as the dividing water content of strain softening and strain hardening in compacted loess samples.
(5) the microstructural type of compacted loess is a pellet structure, and the basic unit body is mainly pellet, and the pores mainly include two kinds of intergranular pores and inner pores in the pellet. The structure form of compacted loess under the same compaction energy is changed from loose to dense with the initial water content from small to large, from disordered intergranular to ordered intergranular. Arrangement, from isotropic to anisotropic.
(6) for the typical fine-grained soil with special sensitivity to the water, the control of water content is particularly important in the compaction process. The air volume rate can be used as the quality control index of the Loess fill compaction at the same time, and the control standard of the air gas accumulation should be combined with the concrete compacted soil sample. Indoor compaction tests are made, generally not more than 10%. When heavy mechanical compaction is used, the water content in the Loess Fill Construction is best controlled within 2% of the wet side of the optimum water content. Under the condition of the corresponding compaction standard, the deformation and strength index can be reached to the design requirements, and the filling foundation is guaranteed. Or the water stability of the subgrade is more favorable.

【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU444

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 王清,王鳳艷,肖樹芳;土微觀結(jié)構(gòu)特征的定量研究及其在工程中的應(yīng)用[J];成都理工學(xué)院學(xué)報(bào);2001年02期

2 朱建華;;飽和與非飽和壓實(shí)粘性土的抗拉強(qiáng)度影響因素的研究[J];大壩觀測(cè)與土工測(cè)試;1986年04期

3 白冰,周健;掃描電子顯微鏡測(cè)試技術(shù)在巖土工程中的應(yīng)用與進(jìn)展[J];電子顯微學(xué)報(bào);2001年02期

4 方祥位,陳正漢,申春妮;重塑非飽和黃土等p剪切試驗(yàn)[J];重慶大學(xué)學(xué)報(bào)(自然科學(xué)版);2004年09期

5 李順群,賈艷東,沈穎,王強(qiáng);雙應(yīng)力狀態(tài)變量表示方法的正交試驗(yàn)驗(yàn)證[J];遼寧工程技術(shù)大學(xué)學(xué)報(bào);2005年04期

6 何利軍;孔令偉;;土的應(yīng)力-應(yīng)變關(guān)系的一種描述模式[J];工程地質(zhì)學(xué)報(bào);2010年06期

7 趙景波，，陳云;黃土的孔隙與濕陷性研究[J];工程地質(zhì)學(xué)報(bào);1994年02期

8 高國瑞;;黃土顯微結(jié)構(gòu)分析及其在工程勘察中的應(yīng)用[J];工程勘察;1980年06期

9 王釗,胡海英,鄒維列;路堤壓實(shí)的影響因素和壓實(shí)度要求[J];公路;2004年08期

10 周勤;趙發(fā)章;張洪亮;;壓實(shí)度和含水量對(duì)于壓實(shí)黃土力學(xué)特性的影響[J];公路;2006年01期

相關(guān)博士學(xué)位論文 前2條

1 陳濤;山區(qū)機(jī)場(chǎng)高填方地基變形及穩(wěn)定性研究[D];鄭州大學(xué);2010年

2 王梅;中國濕陷性黃土的結(jié)構(gòu)性研究[D];太原理工大學(xué);2010年

本文編號(hào)：1807582