为了研发以盾构渣土为主要材料的溶洞填充注浆材料，实现盾构废弃砂质黏土原位化再生利用，以深圳地铁3号线盾构产生的砂质黏土为主原料，辅以水泥和外加剂，在地铁盾构现场制备下伏溶洞填充材料。先通过室内试验研究不同外加剂、水胶比、胶土比等因素对新型溶洞填充料性能影响规律；
再通过扫描电子显微镜试验及现场试验对所制备溶洞填充料的胶凝情况及实际性能进行研究。研究结果表明： 1)铝钙氧化物类外加剂可显著提高溶洞填充料的强度，1 h抗压强度达到0.479 MPa，28
d抗压强度可达11.048 MPa，该外加剂的加入还可提升材料的水稳定性与抗干缩性能，28 d龄期水稳定系数上升20.5%、干缩值降低63.4%。2)提升胶土比与降低水胶比，均可提升溶洞填充料28 d抗压强度； 当胶土比大于0.3之后，溶洞填充料强度随胶土比的提升增长明显。3)经扫描电子显微镜试验发现，在水化作用下，水泥与铝钙氧化物类外加剂在土体中形成丝状与片状连接，土体孔隙总体积减小，密实性增大，结构间的连接更为紧密，使得溶洞填充料具有较高的强度。4)通过开展溶洞填充料现场应用试验可知，钻芯样平均强度为4.16 MPa，满足实际工程需求。
A novel karst cave filling material with shield waste
muck is developed to realize in-situ recycling of shield waste sandy
clay. Herein, a case study is conducted on the Shenzhen metro line 3, and the
shield tunneling-produced sandy clay is taken as raw
material, supplemented with cement and additives, to prepared filling materials
for karst caves under the tunnel. Additionally, the effects of various
additives, water-to-binder
ratios, and clay-to-binder
ratios on the performance of the novel material are examined through indoor
experiments. The coagulation state and practical performance of the prepared
filling materials are further analyzed using scanning electron microscopy and
field tests. The research results indicate the following: (1) Aluminum-calcium oxide-based additives significantly
improve the strength of the filling material, achieving a 1-hour forming strength of 0.479 MPa and a 28-day
strength of 11.048 MPa. Such additives also enhance the water stability and
shrinkage resistance of the material, with a 20.5% increase in the water
stability coefficient and a 63.4% reduction in shrinkage value at 28 days. (2)
Increasing the clay-to-binder
ratio and decreasing the water-to-binder ratio enhance the unconfined compressive strength of the
filling material at 28 days. The strength of the filling material significantly
increases with the rise in the clay-to-binder ratio when the clay-to-binder ratio exceeds 0.3. (3) Scanning electron microscopy tests
reveal that under hydration effect, cement and aluminum-calcium oxide-based additives form fibrous
and flaky connections within the soil, reducing the overall pore volume and
increasing density, resulting in tighter structural connections that yield
higher strength for the filling material. (4) Field application tests of the
filling material are conducted, with an average core sample strength of 4.16
MPa, meeting engineering requirements.
