为了评价挡块式土工格栅在老路拼接中的加筋效果，结合山东省聊城市滨河路老路改造工程现场试验，建立了土工格栅处治老路拼接的计算模型，研究在道路分级加载情况下路堤填土分别与挡块式土工格栅、普通土工格栅共同受力变形特性，对土工格栅在不同工况的加筋效果、层数效应及宽度效应进行了有限元分析，并将有限元结果与试验结果进行对比，分析了挡块处水平应力。研究结果表明：在新老路拼接中，挡块式土工格栅应变值大于普通土工格栅应变值，格栅端部挡块发挥了侧阻力作用；铺设挡块式土工格栅较普通土工格栅更有效减少不均匀沉降、提高加筋效果；土工格栅铺设位置越靠近路基底部，土工格栅发挥的作用越好；在新老路拼接中，普通土工格栅的设计宽度应大于6 m；当老路开挖台阶宽度小于3 m时，铺设挡块式土工格栅有利于解决普通土工格栅锚固长度不足的问题；研究成果对新老路拼接处的处理有借鉴意义。

The problem of inadequate anchorage length of the ordinary geogrid in old road widening could be solved in view of the baffle-type geogrid, so it was significant to evaluate the reinforced effect of the baffle-type geogrid in old road widening. Based on field tests on reconstruction project of the Riverside Road in Liaocheng city of Shandong Province, a calculation model of geogrid treatment in old road widening was established to investigate the synergistic deformation characteristics of embankment filling with the baffle-type geogrid and the ordinary geogrid respectively under the gradation loading of roads. Moreover, the reinforcement effect, layer effect and width effect of geogrid in different conditions were analyzed by the finite element method. The analysis results were compared with test results, with analyzing the horizontal stress of the baffle. The results show that in old road widening, the strain value of baffle-type geogrid is greater than that of the normal geogrid. As the baffle at the end of geogrid plays a lateral resistance role, it is more effective for baffle-type geogrid to reduce the differential settlement of the road, with the result of improving the reinforced effect. It is discovered that the closer the geogrid is to the road base, the better the role of geogrid plays. The design width of ordinary geogrid should be more than 6 meters. When the width of connection step between the old and the new road is less than 3 meters, it is conductive to solve the problem of the insufficient anchorage length of the ordinary geogrid through laying the baffle-type geogrid. These conclusions may provide references for the settlement of interface between new and old embankments.

为了研究土工格室加筋黄土的剪切性能，采用微型土工格室对不同加筋方式的格室加筋黄土及重塑黄土进行三轴剪切试验，得出加筋黄土及重塑黄土的应力-应变曲线及其抗剪强度指标，研究了加筋黄土和重塑黄土的应力-应变特性，分析了不同加筋方式下的加筋效果并讨论了不同土工格室层数加筋的加固机理。试验结果表明：重塑黄土和土工格栅加筋黄土的应力-应变曲线表现为弱硬化型，而土工格室加筋黄土的应力-应变曲线表现出明显的强硬化特性，4层土工格室加筋黄土的加筋效果最佳，2层土工格室加筋黄土在低围压、较大应变情况下，土工格室的加筋效果可以得到更好的发挥；重塑黄土和土工格栅加筋黄土的应力-应变曲线基本呈双曲线，用邓肯-张模型对其拟合效果很好，土工格室加筋黄土的应力-应变曲线用幂函数式对其逼近效果较好；土工格室加筋显著提高土体的摩擦角和黏聚力，2层土工格室加筋黄土的摩擦角和黏聚力相对重塑黄土分别提高38%和50%，4层土工格室加筋黄土的摩擦角和黏聚力相对重塑黄土分别提高63%和120%，均比土工格栅加筋黄土的高；土工格室的加筋效果优于土工格栅等平面筋材，且格室层数的增加能进一步提高黄土的剪切性能，其原因主要是土工格室“强化带”和“间接影响带”的存在，层数越多，“强化带”和“间接影响带”厚度越大，加筋黄土的抗剪强度会得到进一步提高。试验结果可为实际工程中设计参数的选取提供理论依据。

To investigate shear properties of geocell-reinforced loess, triaxial shear tests were conducted on compacted loess and geocell-reinforced loess with different patterns of reinforcement, by dint of the micro-geocell. The stress-strain curves and shear strength indexes of reinforced loess and compacted loess were obtained. Meanwhile, the stress-strain properties of reinforced loess and compacted loess were investigated. The effect of different reinforcement types was analyzed, and the mechanism of reinforcement with geocell under different layers was discussed. The results show that the stress-strain curves of compacted loess and reinforced loess with geogrid present slight strain-hardening behavior, while the stress-strain curves of geocell-reinforced loess present obvious strong strain-hardening behavior. The reinforcement effect of geocell with 4 layers is optimal, and the reinforcement effect of geocell with 2 layers can act well under the low confining pressure or the large strain. The stress-strain curves of compacted loess and reinforced loess with geogrid are hyperbolas. The fitting effect of such curves by dint of Duncan-Chang model is good. Furthermore, it is better to use power function type to fit the stress-strain curves of reinforced loess with geocell. The friction angle and cohesion of soil increase by the reinforcement with geocell, and the friction angle as well as cohesion of reinforced loess with geocell of 2 layers increases by 38% and 50%, compared with that of compacted loess respectively. Moreover, the friction angle and cohesion of reinforced loess with geocell of 4 layers increase by 63% and 120% respectively, which are higher than that of reinforced loess with geogrid. The reinforcement effect of geocell is better than that of geogrid, and the increase of the layer of geocell can further improve the shear property of loess on account of the existence of “enhanced zone” and “indirect effect zone”. The more the layers are, the larger the thickness of “enhanced zone” and “indirect effect zone” will be. The shear strength of reinforced loess will be improved as well. The results will provide the theoretical basis for the selection of design parameters in the practical engineering.

加筋土结构的动力性能对公路、铁路、边坡和挡墙等实际工程具有重要意义，因此研究筋-土界面的动力剪切特性具有重要意义。试验选用填料为4种不同粒径范围的粗颗粒土：0.5~1.18 mm，1.18~2.36 mm，2.36~4.75 mm，4.75~8 mm，一种方形网孔的土工格栅，土工格栅的网孔尺寸为30 mm×30 mm，在剪切速率分别为0.25，1，2，5 mm·min^-1，相对密实度分别为22%、55%、75%的条件下，研究填料平均粒径与土工格栅网孔尺寸的比值（粒孔比）对土工格栅-粗粒土界面循环剪切特性的影响。研究结果表明：当粒孔比从0.04增大到0.20时，土工格栅-粗粒土界面的剪应力峰值先增大后减小，粒孔比为0.07时，土工格栅-粗粒土界面的剪应力峰值最大；粒孔比分别为0.04，0.07，0.11，0.20时，土样的最终剪缩量分别为2.547，2.583，3.150，5.021 mm，表明随着粒孔比的增大，土样的最终剪缩量增大；同一循环次数下，粒孔比为0.07时，土工格栅-粗粒土界面的剪切刚度最大；粒孔比为0.20时，土工格栅-粗粒土界面的阻尼比最大；同一循环次数下，当剪切速率从0.25 mm·min^-1增大到5 mm·min^-1时，土工格栅-粗粒土界面的剪应力峰值先增大后减小；随着剪切速率的增大，土工格栅-粗粒土试样的最终剪缩量增大；相对密实度分别为22%、55%、75%的条件下，粒孔比为0.07时，剪应力峰值均达到最大值，分别为66.63，76.79，79.17 kPa。

The dynamic properties of reinforced soil structure are important for practical engineering such as construction of highways, railways, slope and retaining walls. Hence, it is necessary to study the dynamic shear characteristics of geogrid-soil interface. Four types of sand, with particle diameters ranging between 0.5-1.18 mm, 1.18-2.36 mm, 2.36-4.75 mm, and 4.75-8 mm, and geogrids with square aperture of size 30 mm×30 mm were tested to study the effect of aperture ratio, i.e., the ratio of the average sand particle size to geogrid aperture size on the dynamic shear behavior of geogrid-coarse soil interface using a large-scale direct shear device. The shear rates obtained are 0.25, 1, 2, and 5 mm·min^-1, respectively, and the corresponding soil densities are 22%, 55%, and 75%, respectively. Experimental studies reveal that when the aperture ratio increases from 0.04 to 0.20, the peak shear stress of interface first increases and then decreases, with the largest peak shear stress of interface occurring at an aperture ratio of 0.07. For aperture ratios of 0.04, 0.07, 0.11, and 0.20, the ultimate vertical displacement of interface are 2.547, 2.583, 3.150, and 5.021 mm, respectively. Thus, the ultimate vertical displacement increases with an increase in the aperture ratio. Under the same cyclic times, the largest shear stiffness of interface and damping ratio of interface occur for aperture ratios of 0.07 and 0.20, respectively. with the increasing of the shear rate from 0.25 mm·min^-1 to 5 mm·min^-1, the peak shear stress of interface first increases and then decreases, while the ultimate vertical displacement increases continuously. The peak shear stress of interface is the largest for an aperture ratio of 0.07. For soil densities of 22%, 55%, and 75%, the peak shear stress of interface are 66.63, 76.79, and 79.17 kPa, respectively.

加筋土挡墙因具有造价低廉、施工简便等优点而在公路、铁路等交通基础设施中被广泛应用。作为一种轻型柔性支挡结构，加筋土挡墙易产生较大的水平位移。目前已有的加筋土挡墙水平位移计算公式大多忽略了加筋区整体在土压力作用下产生的水平位移，有必要提出一种准确计算加筋土挡墙总水平位移的解析式。将加筋土挡墙总水平位移分为加筋区内部筋材伸长产生的水平位移和加筋区整体在土压力作用下产生的水平位移两部分。假定加筋区内部破裂面由0.3H法确定，根据胡克定律建立计算加筋区内部由于筋材伸长产生的水平位移解析式；假定加筋区为一复合弹性体，根据虚功原理建立加筋区整体在土压力作用下产生的水平位移解析式，两部分共同构成了加筋土挡墙的总水平位移。结果表明：随着填土模量、填土内摩擦角、填土黏聚力、筋材抗拉刚度和筋材长度的增大，加筋土挡墙的最大水平位移逐渐减小；筋材伸长产生的位移占总位移的比值随填土模量、填土内摩擦角、筋材长度的增大而增大，随填土黏聚力和筋材抗拉刚度的增大而减小；与原型试验测试值和数值模拟值相比，该解析计算结果可反映加筋土挡墙墙体位移沿墙高的分布规律，同时与既有经验公式相比，该方法计算结果更接近实际值。

Reinforced soil retaining walls are widely used in transportation infrastructures, such as highway and railway engineering, because of their characteristics of low cost and easy construction. As a type of light retaining structure, the reinforced soil retaining wall is more susceptible to large lateral deformation. Considering that the current calculation formulas for the lateral displacement of reinforced soil retaining walls mostly ignore the displacement of the unreinforced zone under the earth pressure, it is necessary to propose an accurate analytical formula to calculate the lateral displacement of reinforced soil retaining walls. The lateral displacement of reinforced soil retaining walls was divided into two parts:the displacement induced by the reinforcement extension in the reinforced zone and the displacement in the unreinforced zone. It is assumed that the rupture surface of the reinforced zone was 0.3H curve and the displacement in the reinforced zone was calculated based on Hooke's law. The reinforced zone was assumed to be a composite elastic zone and the displacement of the unreinforced zone was calculated based on the principle of virtual work. The analytical formula was established based on these expectations. The parametric analysis shows that the maximum displacements decrease when accompanied by increasing the filling modulus, friction angle, cohesion, tensile stiffness, and length of reinforcement. The ratio of displacement in the reinforced zone to the total displacement increases when increasing the filling modulus, friction angle, and reinforcement length and it decreases when increasing the cohesion of fill and tensile stiffness of reinforcement. The displacements calculated using this formula have similar trends with the results measured in the field and results calculated using numerical simulation. Meanwhile, the maximum displacements calculated using this formula are closer to the actual values when compared with the existing empirical methods.

In order to study the shear characteristics of fiber reinforced unsaturated soil, the widely distributed unsaturated clay in Shaoxing area is taken as the research object, the polypropylene fiber is used as the reinforced material. The effect of fiber length on the shear deformation characteristics, the shear strength and its indicator of reinforced soil is discussed through a series of unsaturated direct shear tests, and the strengthening mechanism of polypropylene fiber is briefly analyzed. In this way, the optimal fiber length with the best reinforcement effect under 0.2 % addition is obtained. The results show that with the increase of net normal stress, the shear stress-shear displacement curve of soil gradually transforms from softening type to hardening type, and the shear hardening effect is most obvious for the reinforced soil with fiber length of 12 mm. The shear strength of fiber reinforced unsaturated soil is higher than that of plain soil under different net normal stress. With the increase of fiber length, the cohesion strength of fiber reinforced soil first increases and then decreases, and the internal friction angle first increases and then tends to smooth. When the fiber length is 12 mm, the reinforcement effect of polypropylene fiber on the soil shear strength indicator can be maximized.

客土喷播是边坡及矿山修复的一种重要方式。为了找到客土喷播基材中纤维材料的最优纤维长度及掺量,通过室内直接剪切试验研究了不同长度及掺量的椰丝纤维加筋土体的抗剪强度特性,并对土-纤维剪切界面的纤维数量特征进行了统计分析。结果表明:不同长度椰丝纤维加筋土体的抗剪强度随着法向应力的增加呈线性增加趋势,这符合摩尔-库伦定律的基本规律;纤维长度对土体抗剪强度及其参数(内聚力和内摩擦角)的影响显著大于纤维掺量的影响,在纤维长度为3 cm时,土体内聚力达到最大,在纤维长度为4 cm时,内摩擦角达到最大;最优长度对抗剪强度的影响在不同法向应力下表现出一定差异性,随着法向应力的增加,最优纤维长度也增加;纤维长度和掺量对界面纤维数量、数量差值及纤维分散系数都有显著的影响;椰丝纤维在剪切面上的根数与纤维掺量之间并非线性关系,而是呈现指数型上升的趋势;随着纤维长度的增加,界面纤维数量差值呈现先下降后上升的趋势,而纤维的分散系数整体呈现线性上升的趋势,这对纤维在土体中的分散带来一定的考验。总之,椰丝纤维作为一种可持续性的植物纤维材料,加筋土体时可增强土体的界面作用力,明显提升土体的抗剪强度,有利于边坡的稳定,具有广阔的应用前景。