石灰改良红层无侧限抗压强度试验研究

红层是一种特殊岩土，作为路基材料时，常会导致不均匀沉陷、翻浆冒泥等病害。为改善其力学性质，工程上通常掺入一定剂量的石灰（Ca（OH）₂）进行改良。由于降水-蒸发的周期性变化，运营期间反复干湿循环作用对路基土的工程性质造成较大影响。基于此，结合室内无侧限抗压强度试验，研究了干湿循环作用对不同掺量的石灰改良红层无侧限抗压强度的影响。结果表明：在最佳含水率下，石灰改良红层的无侧限抗压强度随石灰掺量的增加而增大；干湿循环作用对改良红层无侧限抗压强度的影响与石灰掺量有关，石灰掺量较低时，改良红层的抗压强度随干湿循环次数的增加而减小，石灰掺量较高时，改良红层的无侧限抗压强度随干湿循环次数的增加而显著增大；未改良红层塑性较大，试样均为塑性鼓胀破坏，掺入石灰后，红层强度增大，脆性增强，呈脆性剪切破坏，经历干湿循环作用后，石灰改良红层试样呈多缝锥形破坏。

Experimental study on the unconfined compressive strength of lime stabilized red-mudstone

Red-mudstone is a kind of special soil. When the weathering red-mudstone was used as the filling materials，lots of engineering problems appeared， such as the uneven settlement， the lower bearing capacity and shoulder of road gushing， etc. In order to improve its mechanical properties， a certain amount of lime （Ca（OH）₂） is usually added in engineering. However， the cyclic drying and wetting during operation has a great influence on the engineering properties of roadbed soil due to periodic variation of rainfall and draught. A series of unconfined compression tests were conducted to study the influence of wetting-drying cycle on the unconfined compressive strength of the stabilized red-mudstone with different content of lime. The test results show that the unconfined compressive strength of the stabilized red-mudstone increases with the increase of the content of lime. The influence of wetting-drying cycle on the unconfined compressive strength of the stabilized red-mudstone is related to the content of lime. When the content of lime is low， the compressive strength of the stabilized soil decreases with the increase of the number of wetting-drying cycles. When the content of lime is high， the unconfined compressive strength of the stabilized soil increases significantly with the increase of the number of wetting-drying cycles. The destruction model of untreated red-mudstone specimens is plastic bulging failure. Due to the increase of soil strength and brittleness， the lime stabilized red-mudstone specimens show brittle shear failure. After the wetting-drying cycle， the destruction model of lime stabilized red-mudstone specimens is cone-shape failure.