This study presents a new method to calculate the passive earth pressure on the rigid retaining wall of non-cohesive limited-width backfill. The proposed method considers the non-cohesive backfill behind the wall as the research object. It was assumed that under the translational mode of the retaining wall, the fracture surface was the plane passing through the heel of the wall and that the principal stress trajectory of the backfill was arc-shaped. The backfill was divided into several arc thin-layer elements by layering along the principal stress trajectory. The non-uniformity of stress distribution on the upper and lower surfaces of the elements was considered. The proposed method was validated with the data obtained from the model tests found in the literature. The results showed that compared with the common horizontal element layering method, the arc thin-layer element method can accurately consider the complex stress acting on the element and better reflect the variation law of the passive earth pressure on the retaining wall. The passive earth pressure of limited-width backfill presented a non-linear distribution along the height of the wall and increased with an increase in soil depth. With an increase in the aspect ratio of soil or a decrease in the internal friction angle, the resultant force of the passive earth pressure gradually decreased while the height of the action point of the resultant force gradually increased. When calculating the passive earth pressure on the retaining wall of limited-width backfill, the critical aspect ratio of limited-width to semi-infinite width was 3.

Abstract To investigate the passive earth pressure of finite soil behind retaining walls, this study considered the principal stress deflection caused by the arching effect of soils. To this end, the shape of the principal stress trajectory was simplified to a straight line, and the finite soil behind retaining walls was divided into several thin-layer elements along the simplified straight line. Subsequently, the calculation formulas for the passive earth pressure distribution, resultant force, and height of its action point were obtained based on the limit equilibrium condition of the thin-layer elements. In addition, the correctness and rationality of the proposed method were verified by comparing its values to those of previously reported experiments and theories. The parameter analysis revealed that the resultant force of passive earth pressure decreased significantly at the initial stage with an increase in the aspect ratio of the finite soil and then remained constant, whereas the height of the action point of resultant force increased gradually and then remains unchanged.

To study the active earth pressure of finite soil behind the retaining wall, the cohesionless soil behind the wall is taken as the research object. The fracture surface is assumed as the plane passing through the heel of the wall, and in the translational mode of the retaining wall, the soil behind the retaining wall forms an arc-shaped small principal stress arch. The soil behind the retaining wall is divided into several curve thin-layer elements by the stratification method along the small principal stress. Considering the inhomogeneity of stress distribution on the upper and lower surface of the element, a calculation method is proposed for the active earth pressure of finite soil retaining wall. The expressions of active earth pressure resultant force and the height of its action point are given, and the correctness of this method is verified. The results show that the curve thin-layer element method can accurately consider the complex stress condition of the element, and can better reflect the variation law of the active earth pressure of finite soil behind the retaining wall. The active earth pressure shows a nonlinear distribution along the wall height H, it firstly increases with the soil depth increasing, then decreases monotonically near the bottom of the wall. In parameter sensitivity analysis, the distribution of active earth pressure of retaining wall and the height of combined force applied point are analyzed with different width-height ratios of soil and wall back roughness. The results show that with the increase of width-height ratio n, the active earth pressure gradually increases, the curve of earth pressure distribution becomes more and more nonlinear, the height of resultant force application point gradually decreases, and it is always greater than H / 3 . It tends to be stable when n is greater than 0.71, so n = 0.71 can be assumed as the critical width-height ratio of finite soil and semi-infinite soil. The active earth pressure decreases gradually with the increase of the frictional angle delta ; the curve of earth pressure distribution becomes more and more nonlinear, the height of resultant force application point increases gradually and is always greater than H / 3 .

Icing has become an important factor to endanger the safe and stable operation of transmission line,and the real-time detection of icing thickness can effectively prevent the serious icing disaster.Firstly identify the transmission line edge through image preprocessing,image segmentation,morphological processing,edge detection and other steps,and then extract the edge line through the Hough transform line detection,finally calculate the ice thickness using the image pixels and the actual wire diameter ratio.The results show that the error between the detected ice thickness and actual measurement is small,and the method is of great significance in ice prevention and removal.

Through cases collection and statistical analysis,causes and hazards of unsymmetrical pressure tunnel were studied.Influence factors of critical depth of unsymmetrical pressure tunnel were analyzed as well as principle of control measures.Results show that causes of unsymmetrical pressure tunnel are terrain,geology and construction.The terrain is major factor,especially in shallow cover section of tunnel entrance.It is more susceptible to occur shear failure and overall unstable failure due to unsymmetrical pressure acting on lining and surrounding rock.Critical depth is proportional to rock condition,tunnel span and surface gradient.In view of reducing degree of bias,comprehensive measures are taken both on ground surface and inside tunnel,such as backfill bias,bias retaining walls,pre-stressed anchor and half-light structure.

Safety influence of operating road tunnel caused by 3 types of structure diseases,such as material degradation of tunnel concrete,insufficient thickness of lining and cavity behind lining,was studied systematically based on structure-load plane analysis model.The results show:(1) the minimum safety factor of lining structure section declines linearly with concrete degrading,especially the degrading local position;(2) structure stiffness decreases directly because of insufficient thickness of lining,and the safety performance of insufficient position declines too;(3) mode of stress and strain is changed because of the existence of cavity behind lining which is the maximum influence factor,especially,if the cavity scope exceeds 2 m.Acted by surrounding rock load,serious structure disease will appear on the lining structure including cracking and spalling till to lose its bearing capacity completely or out of normal service condition.

Using numerical simulation finite-element method,the vertical supporting capacity of large diameter predrilled cast-in-place pile is calculated.The influences of different thickness of bottom settlings are analyzed under pile and mud cakes around pile on the ultimate supporting capacity of single pile.The importance of controlling the thickness of bottom settlings and mud cake is discussed.Some particular measures were put forward as well.

介绍了CFG桩复合地基加固软土地基的原理,通过中山市番中公路中山港大桥收费站改建工程实例,提出了采用CFG桩复合地基加固软土地基的施工方法、施工质量控制事项.

通过对加筋水泥土的实验数据和纯水泥土进行比较，讨论了加筋水泥土的优良性能，分析了加筋水泥土的使用前景。

介绍了高性能混凝土(HPC)国内外研究现状及特性,并从HPC的配合比设计与施工方面进行了探讨,同时结合目前的研究和应用现状论述了其应用前景.

以某座立交桥为实例,具体分析了PC空心板在施加预应力时,板端倒角部位出现纵向裂纹原因并提出了相应的防治措施.试验表明,此裂纹对PC空心板的正常使用没有影响.

详细说明了土工合成材料的种类、特征及功能，并结合工程实例介绍了土工合成材料在公路工程中的应用。

本文介绍了桩承土工合成材料复合地基在软土地基处理中的应用,从定性上分析了桩承土工合成材料复合地基的加固机理,并提出采用太沙基土拱理论和顾淦臣圆形边界张拉薄膜理论推导的计算公式对桩承土工合成材料复合地基进行设计计算的方法.

通过温缩试验对二灰碎石基层材料的温缩性能进行研究,介绍了试验实施方案,并对试验结果进行了分析,得出有关重要结论.对于二灰碎石基层材料的理论研究和实际工作有一定的指导意义.

根据室内直槽修筑的4段典型的半刚性基层沥青路面结构，对路面结构的弯沉进行测定，并通过分析计算，对弯沉的实测值和理论值进行对比分析，验证了交通部“八五”科技项目“沥青路面设计指标与参数的研究”推荐的路面材料设计参数与弯沉综合修正系数等的合理性。